Hepatotoxicity of herbal remedies

Ethnobotanical study on herbal tea drinks in Guangxi, China

BACKGROUND

Herbal tea drinks, different from classical Camellia beverages, are a wide variety of herbal drinks consumed for therapeutic purposes or health promotion. Herbal tea is widely consumed in Guangxi. However, the documentation on the plants for herbal tea and their related health benefits is still limited.

METHODS

An ethnobotanical survey was conducted in 52 villages and 21 traditional markets in Guangxi from 2016 to 2021. Semi-structured interviews, key informant interviews, and structured questionnaires were applied to obtain ethnobotanical information of herbal tea, in which 463 informants had participated. Relative frequency of citation (RFC) and cultural food significance index (CFSI) were used to evaluate the most culturally significant herbal tea plants, and informant consensus factor (ICF) was applied to assess the agreement among informants.

RESULTS

This study recorded 155 herbal tea species belonging to 49 families. The most commonly used parts included leaf (27.61%), whole plant (22.09%), branch and leaf (19.02%), and flower (13.50%). The most frequent preparation method of herbal tea was decoction. Herbal tea was very popular in Guangxi, attributing to its therapeutic value, special odor, and good taste. There are 41 health benefits classified into eight categories. Among them, clearing heat was the most medicinal effects. Local people had high consistency in tonic, removing cold and cough, improving blood circulation, and clearing heat away. Based on CFSI values of each species, the most culturally significant herbal tea species were Siraitia grosvenorii (Swingle) C. Jeffrey ex A. M. Lu & Zhi Y. Zhang, Plantago asiatica L., Gynostemma pentaphyllum (Thunb.) Makino, Zingiber officinale Roscoe, Pholidota chinensis Lindl., and Morus alba L.

CONCLUSION

Herbal tea is a valuable heritage that carries the local people's traditional knowledge, like health care and religious belief. The recorded herbal tea species in this study possess tremendous potential for local economic development in the future. Further research on efficacy evaluation and product development of herbal tea species is necessary.

Investigating the effect of the Teucrium polium aqueous extract on the liver of the streptozotocin-induced diabetic rats

OBJECTIVES

Teucrium polium (TP) has been traditionally used for treatment of the diabetes mellitus, kidney and liver diseases, and inflammations but some studies have reported the hepatotoxicity effects of this plant. Therefore, this study was conducted to investigate the effect of TP aqueous extract on the liver of the diabetic rats.

METHODS

Adult male Wistar rats were randomly divided into five groups: (Control) Normal rats that were gavaged with normal saline (1 mL), (TP100) Normal rats (Non-diabetic) that were gavaged with TP (100 mg/kg), (DM) diabetic model rats, which became diabetic by intraperitoneal injection of streptozotocin (50 mg/kg), (DTP100) diabetic rats that were gavaged with TP (100 mg/kg), and (DTP200) diabetic rats that were gavaged with TP (200 mg/kg). The effects of the aqueous extract on the blood glucose, body weight, the activities of enzyme markers of liver damage (Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT)) were investigated in the serum of the control and treated groups. At the end of study liver histopathology and the total antioxidant activity (TAA) test were evaluated. Finally, obtained data were analyzed by the SPSS software (version 16).

RESULTS

Results showed that the AST and ALT levels were significantly increased in the diabetic rats (p<0.001). A comparison of 100 mg/kg and 200 mg/kg doses of TP administration in diabetic rats also showed a significant difference (p=0.01), indicating a better performance of 100 mg/kg dose. No significant difference was found between the control group and rats treated by the TP (TP100) (p=0.382). Also, triglyceride (TG) and cholesterol levels were significantly decreased in the treated groups compared to the diabetic untreated group.

CONCLUSIONS

Findings of the study revealed no hepatotoxicity, and the hepatoprotective effects of the TP were proved in the present study.

[Drug-induced liver injury-significance of pathology]

Many different medical agents, herbal products, and dietary supplements can induce drug-induced liver injury (DILI) as a clinically relevant complication. DILI, which is direct toxic or idiosyncratic, can have a broad spectrum of clinical appearances from elevation of liver enzymes to acute liver failure. DILI is categorized clinically according to the pattern of serum parameters or pathologically according to the pattern of histomorphology. Histopathological patterns can be described as hepatitic, granulomatous, cholestatic, ductopenic, fibrotic, steatotic, steatohepatitic, and vascular. Correlation to the corresponding drug can be carried out with the corresponding databases (US National Library of Medicine, Liver Tox; www.ncbi.nlm.nih.gov/books/NBK547852/ ). Liver biopsy, in contrast to a clinical/serological diagnostic, has the advantage of an exact resolution with evidence of pathophysiology, activity, regeneration, chronification, and prognosis. Co-occurrence of underlying liver disease can be excluded or confirmed. Histological patterns of DILI are described and illustrated. A diagnostic algorithm for the interpretation of liver biopsies is provided.

Unraveling the Molecular Mechanism of Traditional Chinese Medicine: Formulas Against Acute Airway Viral Infections as Examples

Herbal medicine, including traditional Chinese medicine (TCM), is widely used worldwide. Herbs and TCM formulas contain numerous active molecules. Basically, they are a kind of cocktail therapy. Herb-drug, herb-food, herb-herb, herb-microbiome, and herb-disease interactions are complex. There is potential for both benefit and harm, so only after understanding more of their mechanisms and clinical effects can herbal medicine and TCM be helpful to users. Many pharmacologic studies have been performed to unravel the molecular mechanisms; however, basic and clinical studies of good validity are still not enough to translate experimental results into clinical understanding and to provide tough evidence for better use of herbal medicines. There are still issues regarding the conflicting pharmacologic effects, pharmacokinetics, drug interactions, adverse and clinical effects of herbal medicine and TCM. Understanding study validation, pharmacologic effects, drug interactions, indications and clinical effects, adverse effects and limitations, can all help clinicians in providing adequate suggestions to patients. At present, it would be better to use herbs and TCM formulas according to their traditional indications matching the disease pathophysiology and their molecular mechanisms. To unravel the molecular mechanisms and understand the benefits and harms of herbal medicine and TCM, there is still much work to be done.

Hepatotoxicity in an Adolescent with Black Iced Tea Overconsumption

Tea is the most widely consumed beverage after water in the world. The consumption of iced tea has increased in Western countries and spiked among teenagers for enjoyment, freshening up and alertness. A teenager presented with symptoms of hepatitis. Liver ultrasound revealed sludge in the gallbladder. Laboratory investigations excluded all known causes of hepatotoxicity. Detail nutritional history revealed that the patient had been drinking 1.5-2 liters of black iced tea per day for the last three months. He was immediately advised to stop drinking any tea. Gradually all symptoms disappeared and two months after discontinuation of the tea, all liver enzymes returned to normal and the sludge in the gallbladder disappeared. This case report underlines the importance of a meticulous assessment of a child's dietary behavior when investigating a case of hepatotoxicity and raises awareness about the potential side effects of tea overconsumption.

A billion cups: The diversity, traditional uses, safety issues and potential of Chinese herbal teas

ETHNOPHARMACOLOGICAL RELEVANCE

Herbal teas have long been consumed by Chinese people for preventive and/or therapeutic healthcare. Although herbal teas are widely consumed by many cultural groups in different regions of China, no thorough review has been undertaken to assess the diversity of the country's herbal tea usage. This literature review, complemented by a quantitative survey in an important tea market in Kunming, begins to fill this knowledge gap.

AIMS OF THE STUDY

The study aims to summarize the current knowledge of plant species used as herbal teas by different cultural groups in different regions of China, with a focus on the teas' perceived traditional healthcare functions, related phytochemical/pharmaceutical research, and safety issues.

MATERIALS AND METHODS

The study involved a comprehensive literature review and a market survey. The literature review was based on published ethnobotanical studies of herbal teas in China. We searched the Web of Science™, ELSEVIER, the China National Knowledge Infrastructure (CNKI) and the China Science and Technology Journal Database to locate relevant studies (including journal articles, Masters/PhD dissertations and books) that were published before March 2017. A species list was compiled based on the review and supplemented with information retrieved from the Scifinder database (https://scifinder.cas.org) and the Chinese Pharmacopoeia (2010). A Use Value Index was employed for ranking the most cited species. Based on the 29 most cited species, we discussed the current research status in relation to healthcare benefits and safety concerns of herbal teas in China. To better understand the current status of the herbal tea market in China, we also surveyed 136 tea vendors at the Xiongda Tea Market in Kunming. Information gathered from the survey included the species sold, the sale prices and the form of the herbal tea product.

RESULTS

The literature identified 759 plant species used as herbal tea in China and the market survey identified an additional 23 species. Most of the species used were from the Leguminosae, Compositae and Lamiaceae families. Twenty two provinces and fourteen ethnic minority groups have records on the consumption of herbal teas. Southern China uses up to 82% of the total species, and 211 out of 759 species are used by minority groups. Thirty categories of traditional healthcare functions are linked with herbal teas, with clearing away heat, relieving toxicity and suppressing cough being the most important functions. There is phytochemical/pharmaceutical evidence to support the claimed healthcare benefits of some Chinese herbal teas. Although Chinese herbal teas are generally safe to consume, overdoses of some herbal teas and some unapproved mixtures of species may cause health risks. Based on our market survey, the prices of most herbal teas range between 100 and 200 RMB (US$15-30) per kg.

CONCLUSIONS

A rich array of herbal tea species with various traditional healthcare functions have long been used in China, and as such there is a huge market potential for Chinese herbal teas. More pharmaceutical/phytochemical research is needed to assess a wide range of perceived healthcare benefits of Chinese herbal teas. Our research highlights the need to study herbal teas through an ethnopharmacological perspective and by employing a holistic approach, which requires greater consideration of traditional knowledge in the pharmacological research design. Product safety and sustainability issues should also be considered, so the traditional applications of herbal teas can be transformed to efficient health boosting functional products.

Antidiarrheal Activity of Dissotis multiflora (Sm) Triana (Melastomataceae) Leaf Extract in Wistar Rats and Subacute Toxicity Evaluation

The present work was undertaken to evaluate antidiarrheal activity of ethanolic leaf extract of Dissotis multiflora (Sm) Triana (D. multiflora) on Shigella flexneri-induced diarrhea in Wistar rats and its subacute toxicity. Diarrhea was induced by oral administration of 1.2 × 10⁹ cells/mL S. flexneri to rats. Antidiarrheal activity was investigated in rats with the doses of 111.42 mg/kg, 222.84 mg/kg, and 445.68 mg/kg. The level of biochemical parameters was assessed and organs histology examined by 14 days' subacute toxicity. S. flexneri stool load decreased significantly in dose-dependent manner. The level of ALT increased (p < 0.05) in male rats treated with the dose of 445.68 mg/kg while creatinine level increased in rats treated with both doses. In female rats, a significant decrease (p < 0.05) of the level of AST and creatinine was noted in rats treated with the dose of 222.84 mg/kg of D. multiflora. Histological exams of kidney and liver of treated rats showed architectural modifications at the dose of 445.68 mg/kg. This finding suggests that D. multiflora leaf extract is efficient against diarrhea caused by S. flexneri but the treatment with doses lower than 222.84 mg/kg is recommended while further study is required to define the exact efficient nontoxic dose.

Antibacterial activities of medicinal plants used in Mexican traditional medicine

ETHNOPHARMACOLOGICAL RELEVANCE

We provide an extensive summary of the in vitro antibacterial properties of medicinal plants popularly used in Mexico to treat infections, and we discuss the ethnomedical information that has been published for these species.

MATERIALS AND METHODS

We carried out a bibliographic investigation by analyzing local and international peer-reviewed papers selected by consulting internationally accepted scientific databases from 1995 to 2014. We provide specific information about the evaluated plant parts, the type of extracts, the tested bacterial strains, and the inhibitory concentrations for each one of the species. We recorded the ethnomedical information for the active species, as well as their popular names and local distribution. Information about the plant compounds that has been identified is included in the manuscript. This review also incorporates an extensive summary of the available toxicological reports on the recorded species, as well as the worldwide registries of plant patents used for treating bacterial infections. In addition, we provide a list with the top plant species with antibacterial activities in this review RESULTS: We documented the in vitro antibacterial activities of 343 plant species pertaining to 92 botanical families against 72 bacterial species, focusing particularly on Staphylococcus aureus, Mycobacterium tuberculosis, Escherichia coli and Pseudomonas aeruginosa. The plant families Asteraceae, Fabaceae, Lamiaceae and Euphorbiaceae included the largest number of active species. Information related to popular uses reveals that the majority of the plants, in addition to treating infections, are used to treat other conditions. The distribution of Mexican plants extended from those that were reported to grow in just one state to those that grow in all 32 Mexican states. From 75 plant species, 225 compounds were identified. Out of the total plant species, only 140 (40.57%) had at least one report about their toxic effects. From 1994 to July 2014 a total of 11,836 worldwide antibacterial patents prepared from different sources were recorded; only 36 antibacterial patents from plants were registered over the same time period. We offered some insights on the most important findings regarding the antibacterial effects, current state of the art, and research perspectives of top plant species with antibacterial activities in vitro.

CONCLUSIONS

Studies of the antibacterial in vitro activity of medicinal plants popularly used in Mexico to treat infections indicate that both the selection of plant material and the investigation methodologies vary. Standardized experimental procedures as well as in vivo pharmacokinetic studies to document the effectiveness of plant extracts and compounds are necessary. This review presents extensive information about the medicinal plants possessing antibacterial activity that has been scientifically studied and are popularly used in Mexico. We anticipate that this review will be of use for future studies because it constitutes a valuable information tool for selecting the most significant plants and their potential antibacterial properties.

Liver toxicity mechanisms of herbs commonly used in Latin America

Mexico owns approximately 4500 medicinal plants species, a great diversity that position it at the second place after China. According to the Mexican health department, 90% of common population consumes them to treat various diseases. Additionally, herbal remedies in Latin America (LA) are considered a common practice, but the frequency of use and the liver damage related to its consumption is still unknown. Despite the high prevalence and indiscriminate herbal consumption, the exact mechanism of hepatotoxicity and adverse effects is not fully clarified and is still questioned. Some herb products associated with herb induced liver injury (HILI) are characterized by presenting a different chemical composition that may vary from batch to batch, also the biological activity of many medicinal plants and other natural products are directly related to their most active component and its concentration. There are two main biological components that are associated with liver damage, alkaloids, and flavonoids, which are frequent constituents of commonly used herbs. The interaction with the different cytochrome P-450 isoforms, inflammatory, and oxidative activities seem to be the main damage pathway involved in the liver. It is important to know the herbal adverse effects and mechanisms involved; therefore, this article is focused on the beneficial and deleterious effects as well as the possible toxicity mechanisms and interactions of the herbs that are frequently used in LA, since the herb-host interaction may not always be the expected or desired depending on the clinical context in which it is administered.

Drug Induced Liver Injury: Can Biomarkers Assist RUCAM in Causality Assessment?

Drug induced liver injury (DILI) is a potentially serious adverse reaction in a few susceptible individuals under therapy by various drugs. Health care professionals facing DILI are confronted with a wealth of drug-unrelated liver diseases with high incidence and prevalence rates, which can confound the DILI diagnosis. Searching for alternative causes is a key element of RUCAM (Roussel Uclaf Causality Assessment Method) to assess rigorously causality in suspected DILI cases. Diagnostic biomarkers as blood tests would be a great help to clinicians, regulators, and pharmaceutical industry would be more comfortable if, in addition to RUCAM, causality of DILI can be confirmed. High specificity and sensitivity are required for any diagnostic biomarker. Although some risk factors are available to evaluate liver safety of drugs in patients, no valid diagnostic or prognostic biomarker exists currently for idiosyncratic DILI when a liver injury occurred. Identifying a biomarker in idiosyncratic DILI requires detailed knowledge of cellular and biochemical disturbances leading to apoptosis or cell necrosis and causing leakage of specific products in blood. As idiosyncratic DILI is typically a human disease and hardly reproducible in animals, pathogenetic events and resulting possible biomarkers remain largely undisclosed. Potential new diagnostic biomarkers should be evaluated in patients with DILI and RUCAM-based established causality. In conclusion, causality assessment in cases of suspected idiosyncratic DILI is still best achieved using RUCAM since specific biomarkers as diagnostic blood tests that could enhance RUCAM results are not yet available.

The protective effect of the natural compound hesperetin against fulminant hepatitis in vivo and in vitro

BACKGROUND AND PURPOSE

Liver diseases are mostly accompanied by inflammation and hepatocyte death. Therapeutic approaches targeting both hepatocyte injury and inflammation are not available. Natural compounds are considered as potential treatment for inflammatory liver diseases. Hesperetin, a flavonoid component of citrus fruits, has been reported to have anti-inflammatory properties. The aim of this study was to evaluate the cytoprotective and anti-inflammatory properties of hesperetin both in vitro and in models of fulminant hepatitis.

EXPERIMENTAL APPROACH

Apoptotic cell death and inflammation were induced in primary cultures of rat hepatocytes by bile acids and cytokine mixture respectively. Apoptosis was quantified by caspase-3 activity and necrosis by LDH release. The concanavalin A (ConA) and D-galactosamine/LPS (D-GalN/LPS) were used as models of fulminant hepatitis. Liver injury was assessed by alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, liver histology and TUNEL assay and inflammation by inducible NOS (iNOS) expression.

KEY RESULTS

Hesperetin blocked bile acid-induced apoptosis and cytokine-induced inflammation in rat hepatocytes. Moreover, hesperetin improved liver histology and protected against hepatocyte injury in ConA- and D-GalN/LPS-induced fulminant hepatitis, as assessed by TUNEL assay and serum AST and ALT levels. Hesperetin also reduced expression of the inflammatory marker iNOS and the expression and serum levels of TNFα and IFN-γ, the main mediators of cell toxicity in fulminant hepatitis.

CONCLUSION AND IMPLICATIONS

Hesperetin has anti-inflammatory and cytoprotective actions in models of acute liver toxicity. Hesperetin therefore has therapeutic potential for the treatment of inflammatory liver diseases accompanied by extensive hepatocyte injury, such as fulminant hepatitis.

Steroid Therapy for a Case of Severe Drug-Induced Cholestasis

Objective:

To report a Severe case of cholestatic liver disease successfully treated with corticosteroids following combined therapy with clarithromycin and nimesulide.

Case Summary:

A 15-year-old girl was admitted with cholestasis probably related to treatment with clarithromycin and nimesulide for an upper respiratory tract infection. Other causes of liver disease (infections, metabolic liver disorders, genetic cholestatic syndromes, autoimmune diseases, primary biliary tract disorders) were excluded. Liver biopsy showed a severe canalicular cholestasis with bile plugs in dilated bile canaliculi, giant cell transformation, and portal and lobular infiltrate. An objective causality assessment suggested that cholestasis was probably related to clarithromycin and/or nimesulide use. No benefit was derived from a course of ursodeoxycholic acid therapy. Since the patient experienced a progressive worsening in cholestasis, prednisone was started after 20 days. This therapy was promptly followed by improvement in clinical and laboratory test results. After 2 months of prednisone treatment, the patient became symptom-free with normal liver function tests.

Discussion:

The manifestations of drug-induced hepatotoxicity are highly variable, ranging from asymptomatic hypertransaminemia to fulminant hepatic failure. No specific treatment for drug-induced hepatotoxicity exists. Early recognition and drug withdrawal are the keys to management of hepatotoxicity, but in some cases, liver disease may persist despite discontinuation of the drug. Possible advantages of corticosteroid therapy have not been well demonstrated.

Conclusions:

Application of the Naranjo probability scale indicates a probable relationship between cholestasis and nimesulide plus clarithromycin use. This case draws attention to a possible therapeutic option for some cases of drug-induced hepatotoxicity that show a severe course without any sign of improvement.

Liver toxicity related to herbs and dietary supplements: Online table of case reports. Part 2 of 5 series

BACKGROUND

No online current list of potentially life-threatening, hepatotoxic herbs and dietary supplements based on PubMed case reports exists in a summarized tabular form.

METHODS

Documented case reports of herbs or dietary supplements (DS; includes herbs) appearing to contribute to liver injury were used to create an online "DS Toxic Table" of potentially hepatotoxic herbs and dietary supplements (PubMed, 1966 to June, 2016, and cross-referencing). The spectrum of DS induced liver injuries (DSILI) included elevated liver enzymes, hepatitis, steatosis, cholestasis, hepatic necrosis, hepatic fibrosis, hepatic cirrhosis, veno-occlusive disease, acute liver failure requiring a liver transplant, and death.

RESULTS

Over the past 50 years, approximately 21 herbs (minus germander and usnic acid that are no longer sold) and 12 dietary supplements (minus the nine no longer sold and vitamin A & niacin due to excess intake) posed a possible risk for liver injures in certain individuals. The herbs with the most number of reported publications (but not cases studies) in descending order, were germander, black cohosh, kava extract, and green tea extract.

CONCLUSION

These online DS Toxic Tables will contribute to continued Phase IV post marketing surveillance to detect possible liver toxicity cases and serve to forewarn consumers, clinicians, and corporations.

Herbal Hepatotoxicity: Clinical Characteristics and Listing Compilation

Herb induced liver injury (HILI) and drug induced liver injury (DILI) share the common characteristic of chemical compounds as their causative agents, which were either produced by the plant or synthetic processes. Both, natural and synthetic chemicals are foreign products to the body and need metabolic degradation to be eliminated. During this process, hepatotoxic metabolites may be generated causing liver injury in susceptible patients. There is uncertainty, whether risk factors such as high lipophilicity or high daily and cumulative doses play a pathogenetic role for HILI, as these are under discussion for DILI. It is also often unclear, whether a HILI case has an idiosyncratic or an intrinsic background. Treatment with herbs of Western medicine or traditional Chinese medicine (TCM) rarely causes elevated liver tests (LT). However, HILI can develop to acute liver failure requiring liver transplantation in single cases. HILI is a diagnosis of exclusion, because clinical features of HILI are not specific as they are also found in many other liver diseases unrelated to herbal use. In strikingly increased liver tests signifying severe liver injury, herbal use has to be stopped. To establish HILI as the cause of liver damage, RUCAM (Roussel Uclaf Causality Assessment Method) is a useful tool. Diagnostic problems may emerge when alternative causes were not carefully excluded and the correct therapy is withheld. Future strategies should focus on RUCAM based causality assessment in suspected HILI cases and more regulatory efforts to provide all herbal medicines and herbal dietary supplements used as medicine with strict regulatory surveillance, considering them as herbal drugs and ascertaining an appropriate risk benefit balance.

Herbal hepatotoxicity: current status, examples, and challenges

INTRODUCTION

Herbal medicines have commonly been considered safe by the general public due to their natural origin and long history of traditional uses. In contrast to this belief, many plants produce toxic substances as secondary metabolites that are sometimes not easily distinguishable from the pharmacological active compounds. Some herbal medicines have been associated with adverse effects and toxic effects, including hepatotoxicity, which have been reversed upon discontinuation of the herbal medicine by the patient.

AREAS COVERED

This review reflects on selected herbal medicines that are associated with hepatotoxic effects including a description of the phytochemicals that have been linked to liver injury where available. Although case studies are discussed where patients presented with hepatotoxicity due to use of herbal medicines, results from both in vitro and in vivo studies that have been undertaken to confirm liver injury are also included.

EXPERT OPINION

Increasing evidence of herbal hepatotoxicity has become available through case reports; however, several factors contribute to challenges associated with causality assessment and pre-emptive testing as well as diagnosis of herb-induced liver injury.

Herbal hepatotoxicity in traditional and modern medicine: actual key issues and new encouraging steps

Plants are natural producers of chemical substances, providing potential treatment of human ailments since ancient times. Some herbal chemicals in medicinal plants of traditional and modern medicine carry the risk of herb induced liver injury (HILI) with a severe or potentially lethal clinical course, and the requirement of a liver transplant. Discontinuation of herbal use is mandatory in time when HILI is first suspected as diagnosis. Although, herbal hepatotoxicity is of utmost clinical and regulatory importance, lack of a stringent causality assessment remains a major issue for patients with suspected HILI, while this problem is best overcome by the use of the hepatotoxicity specific CIOMS (Council for International Organizations of Medical Sciences) scale and the evaluation of unintentional reexposure test results. Sixty five different commonly used herbs, herbal drugs, and herbal supplements and 111 different herbs or herbal mixtures of the traditional Chinese medicine (TCM) are reported causative for liver disease, with levels of causality proof that appear rarely conclusive. Encouraging steps in the field of herbal hepatotoxicity focus on introducing analytical methods that identify cases of intrinsic hepatotoxicity caused by pyrrolizidine alkaloids, and on omics technologies, including genomics, proteomics, metabolomics, and assessing circulating micro-RNA in the serum of some patients with intrinsic hepatotoxicity. It remains to be established whether these new technologies can identify idiosyncratic HILI cases. To enhance its globalization, herbal medicine should universally be marketed as herbal drugs under strict regulatory surveillance in analogy to regulatory approved chemical drugs, proving a positive risk/benefit profile by enforcing evidence based clinical trials and excellent herbal drug quality.

Hepatotoxic assessment of Polygoni Multiflori Radix extract and toxicokinetic study of stilbene glucoside and anthraquinones in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Polygoni Multiflori Radix (PMR) has been traditionally used as a tonic and an anti-aging remedy for centuries; however, hepatic lesions linked to PMR have been frequently reported.

AIM OF THE STUDY

This work attempted to investigate the hepatotoxic potential of PMR extract and the toxicokinetics of stilbene glucoside and anthraquinones in PMR extract following repeated administration.

MATERIALS AND METHODS

Histopathological and biochemical tests were performed to assess the hepatotoxicity of PMR extract. A rapid and sensitive liquid chromatography-mass spectrometry (LC-MS) assay was developed for toxicokinetic analysis of the main constituents of PMR extract, including 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG), emodin-8-O-β-D-glucoside and emodin.

RESULTS

The histopathological and biochemical tests indicated that repeated administration of high-dose PMR extract (20 g/kg) for 3 weeks could cause hepatic lesions, while the low-dose treatment (1 g/kg) was safe. Necrosis and steatosis of hepatic cells, inflammatory cell infiltration and mild fibrosis were the main toxicity symptoms caused by high-dose PMR extract in rat liver. The aspartate aminotransferase (AST) levels increased by approximately 17%, from 110.80±0.84 to 129.75±10.83 IU/L, in the high-dose group compared with the control group. The proposed LC-MS method was proven to be suitable for the simultaneous quantification of these three constituents by affording desirable linearity (r(2)>0.998) and satisfactory precision (error less than 10%). The toxicokinetic study showed that emodin could not be detected in the low-dose group, but the AUC and Cmax of emodin displayed a gradual increase with repeated treatments in the high-dose group. The toxicokinetics of TSG in the low- and high-dose groups exhibited similar trends after repeated administration.

CONCLUSIONS

Consideration needs to be given to the rational application of PMR in the clinic to balance its benefits and risks. The increased emodin exposure in vivo provided a putative explanation for the observed hepatic lesions induced by PMR extract, although further studies to confirm the potentially causal link between emodin exposure and hepatic lesions are still necessary.

Herb-induced autoimmune-like hepatitis in C57BL/6J mice

BACKGROUND & AIMS

Animal model suitable for studying herb-induced experimental autoimmune hepatitis (AIH) remains a challenging problem. A medicinal herb containing Scutellaria baicalensis Georgi (Sb) and Bupleurum chinense DC (Bc) has been sporadically reported to be related to liver fibrosis. The aim of this study was to investigate the effects of Sb and Bc on experimental AIH in mice.

METHODS

C57BL/6J mice received intraperitoneal injection of Sb and/or Bc herbal extracts (1 mg/kg) for 4 or 8 weeks. Serum samples were collected to analyse serum transferase (AST, ALT), creatinine, markers for AIH and hepatic cytokine levels such as IFN-γ, IL10 and TGF-β1. Peripheral mononuclear cell (PBMC) gene expression profiles were analysed to show their effects on immune system.

RESULTS

Our results showed that Sb or Bc treatment increased serum AST, ALT, IgG and ANA levels. Prominent necroinflammatory changes were demonstrated in the livers of Sb- or Bc-treated mice while the decrease in IFN-γ and elevation of IL10 and TGF-β1 levels in liver tissues. Furthermore, the PMBC gene expression profile suggested that Sb or Bc treatment could modulate immune responses.

CONCLUSION

We conclude that the presence of AIH in Sb- or Bc-treated mice and C57BL/6J strain mice is a reliable animal model for studying herb-induced AIH-like hepatitis.

[Effect of three herbal extracts on cytochrome P450 and possibility of interaction with drugs]

Herb-drug interactions are mainly mediated by hepatic cytochrome P450 (CYP) enzymes. Here, we examined the effect of three herbs (valerian, salacia and black cohosh) on CYP activity in vivo in mice and in liver microsomes in vitro. Extracts which showed activity in the preliminary tests were then fed to mice at various doses (0, 0.5, 1.5 and 4.5%). Valerian did not show any effect on hepatic CYPs. Black cohosh increased the liver weight, total CYP content and CYP activities (2B and 3A) in a dose-dependent manner (up to 4.5%). Salacia inhibited CYP1A2 activity in liver microsomes in vitro. Also, salacia at the dietary dose of 4.5% suppressed body weight gain, decreased hepatic total CYP content and increased CYP activities (1A1, 2B and 2C). These findings suggest that black cohosh and salacia at high dose affect the activity of hepatic CYPs, and therefore may interact with drugs that are metabolized by CYP.

Hepatoprotective effect of commercial herbal extracts on carbon tetrachloride-induced liver damage in Wistar rats

Background:

Various hepatoprotective herbal products from plants are available in Mexico, where up to 85% of patients with liver disease use some form of complementary and alternative medicine. However, only few studies have reported on the biological evaluation of these products.

Objective:

Using a model of carbon tetrachloride (CCl₄)-induced hepatotoxicity in rats, we evaluated the effects of commercial herbal extracts used most commonly in the metropolitan area of Monterrey, Mexico.

Materials and Methods:

The commercial products were identified through surveys in public areas. The effect of these products given with or without CCl₄ in rats was evaluated by measuring the serum concentrations of aspartate amino transferase (AST) and alanine amino transferase (ALT), and histopathological analysis. Legalon^® was used as the standard drug.

Results:

The most commonly used herbal products were Hepatisan^® capsules, Boldo capsules, Hepavida^® capsules, Boldo infusion, and milk thistle herbal supplement (80% silymarin). None of the products tested was hepatotoxic according to transaminase and histological analyses. AST and ALT activities were significantly lower in the Hepavida+CCl₄-treated group as compared with the CCl₄-only group. AST and ALT activities in the silymarin, Hepatisan, and Boldo tea groups were similar to those in the CCl₄ group. The CCl₄ group displayed submassive confluent necrosis and mixed inflammatory infiltration. Both the Hepatisan+CCl₄ and Boldo tea+CCl₄ groups exhibited ballooning degeneration, inflammatory infiltration, and lytic necrosis. The silymarin+CCl₄ group exhibited microvesicular steatosis. The Hepavida+CCl₄- and Legalon+CCL₄-treated groups had lower percentages of necrotic cells as compared with the CCl₄-treated group; this treatment was hepatoprotective against necrosis.

Conclusion:

Only Hepavida had a hepatoprotective effect.

Herbal hepatotoxicity: a hidden epidemic

Complementary and alternative therapies, including herbal products, have become increasingly popular in the general population and among patients and physicians. Regulations and pharmacovigilance regarding herbal drugs are still incomplete and need to be improved. In fact, herbals are commonly marketed on the Internet, and in many countries they are sold as food supplements, which are beyond the control of drug regulatory agencies. In Europe and the U.S., reports of hepatotoxicity from these products, including those advertised for liver diseases, are accumulating. Many herbal drugs are also commonly used in children, and in women during pregnancy and lactation, because they are believed to be "natural" and, therefore, "harmless." One emerging problem is people preferring herbal-based slimming aids to conventional dietary and physical activity. In Italy, the use of non-conventional therapies has been reported for 13.6 % of the population, and 3.7 % freely use herbal drugs, unaware of the risks associated with a potential interaction with prescription drugs. In our review, we discuss the problem of the lack of standardization of herbal drugs, the lack of randomized clinical trials regarding the majority of these products, the unawareness of risks by the patients who buy and use them, and, further, the problem of underreporting. For the most commonly used herbal products and slimming aids, we describe their potential hepatotoxicity mechanisms, the causality assessment necessary for a correct diagnosis, and the clinical patterns for which these products seem to be responsible.

Herbal hepatotoxicity: a tabular compilation of reported cases

BACKGROUND

Herbal hepatotoxicity is a field that has rapidly grown over the last few years along with increased use of herbal products worldwide.

AIMS

To summarize the various facets of this disease, we undertook a literature search for herbs, herbal drugs and herbal supplements with reported cases of herbal hepatotoxicity.

METHODS

A selective literature search was performed to identify published case reports, spontaneous case reports, case series and review articles regarding herbal hepatotoxicity.

RESULTS

A total of 185 publications were identified and the results compiled. They show 60 different herbs, herbal drugs and herbal supplements with reported potential hepatotoxicity, additional information including synonyms of individual herbs, botanical names and cross references are provided. If known, details are presented for specific ingredients and chemicals in herbal products, and for references with authors that can be matched to each herbal product and to its effect on the liver. Based on stringent causality assessment methods and/or positive re-exposure tests, causality was highly probable or probable for Ayurvedic herbs, Chaparral, Chinese herbal mixture, Germander, Greater Celandine, green tea, few Herbalife products, Jin Bu Huan, Kava, Ma Huang, Mistletoe, Senna, Syo Saiko To and Venencapsan(®). In many other publications, however, causality was not properly evaluated by a liver-specific and for hepatotoxicity-validated causality assessment method such as the scale of CIOMS (Council for International Organizations of Medical Sciences).

CONCLUSIONS

This compilation presents details of herbal hepatotoxicity, assisting thereby clinical assessment of involved physicians in the future.

Determination of emodin in L-02 cells and cell culture media with liquid chromatography-mass spectrometry: application to a cellular toxicokinetic study

The emodin-involved hepatotoxicity has been gaining increasing attention. The purpose of the present study was to evaluate the cytotoxicity of emodin on cultured human liver cells (L-02) and predict the possible relation between its cytotoxicity and cellular toxicokinetics. Cell viability and cell damage were assessed by Cell Counting Kit-8 (CCK-8) assay and phase-contrast microscopy, respectively. Cytotoxicity tests demonstrated a concentration- and time-dependent toxic effect of emodin on L-02 cells. Furthermore, emodin at concentration of 30μM led to a significant apoptosis in a time-dependent manner supported by the morphological changes of drug-treated cells. In addition, to elucidate the toxicokinetic characteristics of emodin, a highly sensitive and selective liquid chromatography-mass spectrometry (LC-MS) method was employed and validated for detecting the dynamic alteration of emodin in cells and cell culture media. The proposed method appeared to be suitable for the analysis of emodin with desirable linearity (r(2)>0.99), and satisfying precision being less than 8.7%. The range of recoveries of this method was 90.2-101.9%. The preliminary cellular toxicokinetic study revealed a time-dependent intracellular accumulation of emodin, which was consistent with its in vitro toxic effects. These findings confirmed the cytotoxicity of emodin against L-02 cells and displayed the cytotoxic manner of emodin in terms of its cellular uptake and accumulation in L-02 cells.

Macro- and micro- elements in some herbal drug raw materials and their water extracts consumed in Poland

The concentrations of seven macro- and microelements (K, Mg, Ca, Na, Fe, Zn, Mn) in 59 herbs (herbs, leaves, flowers, fruits, roots), which are commercially available and frequently used in Poland for medical purposes as well as in their water extracts (infusions and decoctions), were determined after microwave mineralization. The data obtained show that all herbal raw materials analysed contain macroelements in the range of mg g−1 on d.w. whereas microelements in the range of mg kg−1 on d.w. and that elemental concentrations varied widely. On the basis of a comparison of concentrations of elements in herbal raw materials examined and water extracts prepared from them, the extraction efficiency was expressed as a percent of the total content of each element present in the infusion or decoction. The percentages of macro- and micro- elements leaching from different morphological parts of plants into water extracts varied across a wide range of values, from 1% in the case of Na to 56% in the case of K. Real daily intake of the macro- and microelements elements through one cup of infusions or decoctions were shown that water extracts from herbal raw materials are not an important source of bioelements in human diet.

Drug-induced acute liver failure: results of a U.S. multicenter, prospective study

Acute liver failure (ALF) due to drug-induced liver injury (DILI), though uncommon, is a concern for both clinicians and patients. The Acute Liver Failure Study Group has prospectively collected cases of all forms of acute liver failure since 1998. We describe here cases of idiosyncratic DILI ALF enrolled during a 10.5-year period. Data were collected prospectively, using detailed case report forms, from 1198 subjects enrolled at 23 sites in the United States, all of which had transplant services. A total of 133 (11.1%) ALF subjects were deemed by expert opinion to have DILI; 81.1% were considered highly likely, 15.0% probable, and 3.8% possible. Subjects were mostly women (70.7%) and there was overrepresentation of minorities for unclear reasons. Over 60 individual agents were implicated, the most common were antimicrobials (46%). Transplant-free (3-week) survival was poor (27.1%), but with highly successful transplantation in 42.1%, overall survival was 66.2%. Transplant-free survival in DILI ALF is determined by the degree of liver dysfunction, specifically baseline levels of bilirubin, prothrombin time/international normalized ratio, and Model for End-Stage Liver Disease scores.

CONCLUSION

DILI is an uncommon cause of ALF that evolves slowly, affects a disproportionate number of women and minorities, and shows infrequent spontaneous recovery, but transplantation affords excellent survival.

A case of supplement-induced hepatotoxicity

A 45-year-old Caucasian male presented with a two-week history of jaundice and right-upper quadrant (RUQ) abdominal pain. Transaminases and biliary enzymes were markedly elevated with hyperferritinemia and mildly elevated INR. Imaging tests showed no significant abnormality. He denied prescription or over-the-counter (OTC) medication use, but he had been taking at least 9 dietary supplements for 12 months. Other causes of liver disease were excluded. His supplements were discontinued, and his liver-associated enzymes significantly markedly improved over the next 6 weeks and remained normal after one year suggesting supplement-induced hepatotoxicity. Due to the number of supplements, no specific agent could be identified as the primary cause of his liver injury. This case illustrates the importance of inquiring and educating patients of the potential harmful risks of over-the-counter medications and supplements.

[Toxic hepatitis associated with Polygoni multiflori]

Toxic hepatitis has been reported as a major cause of acute hepatitis, but its potential induction by herbal remedies and/or health foods is usually neglected. We experienced a case of toxic hepatitis associated with Polygoni multiflori, a Chinese herb commonly known as Ho-Shou-Wu. A 54-year-old woman consumed Ho-Shou-Wu for 1 month, after which she experienced fatigue and overall weakness. A diagnosis of toxic hepatitis was made based on her clinical history, the findings for viral markers and other laboratory data, and ultrasonography. Her condition improved considerably after she stopped taking Ho-Shou-Wu. However, she resumed taking Ho-Shou-Wu immediately after discharge from hospital, which aggravated her symptoms and liver function. She was immediately readmitted and stopped taking Ho-Shou-Wu. Her relapse into hepatitis immediate after resuming consumption of the herb is strongly indicative of the validity of Koch's postulate in this case.

The Effect of an Aqueous Extract of Teucrium polium on Glutathione Homeostasis In Vitro: A Possible Mechanism of Its Hepatoprotectant Action

Background. Teucrium polium is used in Arab traditional medicine to treat liver diseases. Glutathione is an important intracellular antioxidant, and intrahepatic glutathione levels are depleted in liver diseases. Hypothesis and Aim. This investigation tested the hypothesis that aqueous extracts of T. polium maintains intracellular glutathione levels by augmenting glutathione peroxidase and glutathione reductase activity in cultured hepatocytes. Methods. The effects of increasing concentrations (0.01-1 mg/mL) of aqueous extract of T. polium were assessed in cultured HepG2 cells following 24 hours incubation on (1) cellular integrity using (a) the Trypan blue exclusion assay, (b) the [di-methylthiazol-2yl]-2,5-diphenyl-tetrazoliumbromide (MTT) assay, and (c) the lactate dehydrogenase (LDH) assay; (2) glutathione redox state; and (3) glutathione peroxidase and glutathione reductase activities using a repeated measures experimental design. Results. At concentrations of 0.375 mg/mL and 0.5 mg/mL, the extract increased the intracellular levels of total and reduced glutathione and had no effect on the intracellular amounts of oxidized glutathione. The extract had no effect on glutathione peroxidase and glutathione reductase activities. Conclusion. These data indicate that the mechanism of the hepatoprotective action of aqueous extracts of T. polium may be, in part, due to augmenting intracellular glutathione levels.

Complementary and alternative medicine use in chronic liver disease patients

GOALS

To examine a wide range of sociodemographic and clinical characteristics as potential predictors of complementary and alternative medicine (CAM) use among chronic liver disease (CLD) patients, with a focus on CAM therapies with the greatest potential for hepatotoxicity and interactions with conventional treatments.

BACKGROUND

There is some evidence that patients with CLD commonly use CAM to address general and CLD-specific health concerns.

STUDY

Patients enrolled in a population-based surveillance study of persons newly diagnosed with CLD between 1999 and 2001 were asked about current use of CAM specifically for CLD. Sociodemographic and clinical information was obtained from interviews and medical records. Predictors of CAM use were examined using univariate and multivariate logistic regression analysis.

RESULTS

Of the 1040 participants, 284 (27.3%) reported current use of at least 1 of 3 CAM therapies of interest. Vitamins or other dietary supplements were the most commonly used therapy, reported by 188 (18.1%) patients. This was followed by herbal medicine (175 patients, 16.8%) and homeopathy (16 patients, 1.5%). Several characteristics were found to be independent correlates of CAM use: higher education and family income, certain CLD etiologies (alcohol, hepatitis C, hepatitis C and alcohol, and hepatitis B), and prior hospitalization for CLD.

CONCLUSIONS

Use of CAM therapies that have the potential to interact with conventional treatments for CLD was quite common among this population-based sample of patients with CLD. There is a need for patient and practitioner education and communication regarding CAM use in the context of CLD.

Drug-induced liver injury: insights from genetic studies

Drug-induced liver injury (DILI) is an increasing health problem and a challenge for physicians, regulatory bodies and the pharmaceutical industry, not only because of its potential severity and elusive pathogenesis but also because it is often inaccurately diagnosed, commonly missed entirely and more often not reported. The general view is that idiosyncratic DILI, which is not predictable whether based on the pharmacology of the drug or on the dose administered, is determined by the presence in the recipient of variants in, or expression of, genes coding for key metabolic pathways and/or the immune response, and the interaction of these genetic variants with environmental variables. Furthermore, idiosyncratic DILI is an example of a complex-trait disease with two or more susceptibility loci, as reflected by the frequency of genetic variants in the population often being higher than the occurrence of significant liver injury. Polymorphisms of bioactivation/toxification pathways via the CYP450 enzymes (Phase I), detoxification reactions (Phase II) and excretion/transport (Phase III), together with immunological factors that might determine DILI are reviewed. Challenges such as gene-trait association studies and whole-genome studies, and future approaches to the study of DILI are explored. Better knowledge of the candidate genes involved could provide further insight for the prospective identification of susceptible patients at risk of developing drug-induced hepatotoxicity, development of new diagnostic tools and new treatment strategies with safer drugs.

Acute liver injury associated with the use of herbal preparations containing glucosamine: three case studies

The use of complementary and alternative medicines is becoming increasingly popular in Western society. As a result the number of reported adverse reactions is increasing. Glucosamine is a herbal remedy commonly used to ease joint pain in osteoarthritis, and only two previous reports of hepatotoxicity have been published in the scientific literature. The present report describes three patients who developed acute liver injury following exposure to glucosamine; one patient made a complete recovery on cessation of ingestion, the second developed chronic hepatitis and the third died following progression to fulminant hepatic failure. A diagnosis of glucosamine-induced hepatotoxicity was made based on the temporal relationship between onset of liver injury and glucosamine ingestion, exclusion of all other potential aetiologies and, in the two surviving cases, improvement in condition on withdrawal of the supplement.

Conjugated linoleic acid-induced toxic hepatitis: first case report

A 46-year-old female patient was referred to our department with presenting symptoms of asthenia, jaundice, and pruritus. There was no medical history or clinical evidence of viral hepatitis, autoimmune hepatitis, hemochromatosis, or Wilson's disease. The patient revealed that 14 days prior to admission she had begun self-medicating with conjugated linoleic acid (CLA) to reduce body fat, leading to the suspicion of CLA hepatotoxicity, which was subsequently confirmed by a liver biopsy. After the patient ceased to ingest CLA, liver enzymes levels normalized. To the best of our knowledge, this is the first report of hepatotoxicity due to CLA ingestion.

Severe drug induced acute hepatitis associated with use of St John's wort (Hypericum perforatum) during treatment with pegylated interferon α

A 61-year-old woman with chronic hepatitis C received peginterferon α 180 μg/week, and obtained undetectable qualitative hepatitis C virus (HCV) RNA (lower limit of detection 50 IU/ml) after 8 weeks of treatment. Shortly thereafter aminotransferase values greatly increased (>20 × upper limit of normal) and did not decline after treatment suspension. The patient admitted taking St John's wort (Hypericum perforatum) for depressed mood, recommended by a friend, during the preceding 6 weeks. Liver function tests continued to worsen and international normalised ratio (INR) prolongation developed; the patient was hospitalised. Test for antinuclear antibody was positive (1:320) and treatment with methylprednisolone was started; bilirubin and aminotransferase levels slowly declined, though a new flare occurred when steroids were tapered. After 6 months of prednisone treatment, the liver function tests returned to baseline levels. The combination of peginterferon α and St John's wort resulted in a severe acute hepatitis in this patient. Patients should be advised of this potential toxic effect of this herbal remedy.

Hepatotoxic pyrrolizidine alkaloids in pollen and drying-related implications for commercial processing of bee pollen

Using HPLC-ESI-MS, several saturated and 1,2-dehydropyrrolizidine alkaloids were detected, mainly as their N-oxides, in fresh pollen collected from flowers of the pyrrolizidine alkaloid-producing plants Echium vulgare, E. plantagineum, Senecio jacobaea, S. ovatus, and Eupatorium cannabinum, and/or pollen loads from bees (bee pollen) that foraged on those plants. A major alkaloidal metabolite in S. ovatus was tentatively identified, using its mass spectrometric data and biogenic considerations, as the previously unreported, saturated alkaloid, 2-hydroxysarracine. Heating had very little effect on the 1,2-dehydropyrrolizidine alkaloids and their N-oxides from a variety of sources. Considered in conjunction with international concerns about the adverse effects of these alkaloids, the results strongly indicate a need for monitoring pollen supplies intended for human consumption, at least until conditions for processing and/or selection are clearly defined such as to significantly reduce the hepatotoxic (and potentially carcinogenic and genotoxic) pyrrolizidine alkaloid content of bee pollen.

Inpatient admissions for drug-induced liver injury: results from a single center

Objective To review all cases of drug-induced liver injury (DILI) requiring hospitalization at a single tertiary care center. Methods Patient records were identified by ICD-9 codes for inpatient visits from November 1998 through March 2006. Results Of a total 83,265 hospital admissions during the study period, 40 were for DILI (0.048%). Thirteen patients had non-acetaminophen DILI (NA-DILI); 27 had acetaminophen-related DILI (A-DILI). In the NA-DILI group, mean age was 59 +/- 17.9 years and liver injury was classified as hepatocellular (7), cholestatic (5), or mixed (1). A variety of medications were implicated with antimicrobials being the most common class. Resolution occurred in seven, two died of complications related to hepatotoxicity, one underwent liver transplantation, and the outcome was undetermined in three who were lost to follow-up. In the A-DILI group, mean age was 35 +/- 11.0 years. Eighteen involved intentional overdose of acetaminophen; nine were associated with chronic use. The pattern of injury was hepatocellular in all. Resolution occurred in 4 patients, death in 8, and improvement in 15. Conclusions DILI is a rare cause of inpatient admission but is associated with significant mortality. Spontaneous resolution occurs in most patients but return to normal liver function may take months. Antimicrobial agents account for the largest proportion of NA-DILI.

Lycopodium similiaplex-induced acute hepatitis: a case report

A 46-year-old woman was admitted to our department with symptoms of nausea, anorexia and asthenia. Serum alanine aminotransferase and aspartate aminotransferase levels were increased; all serological tests for viral hepatitis and autoimmune disorders were negative. She had taken Lycopodium similiaplex solution as sedative for the previous 8 weeks, whose two constituents, Lycopodium serratum and Chelidonium majus, are found to be potentially toxic. After discontinuing L. similiaplex use, liver values returned to normal and she was asymptomatic. The diagnosis was definitively confirmed by liver biopsy; on the basis of the histological specimen, a hypersensitivity reaction was hypothesized as a possible pathogenic mechanism. Hepatotoxicity of phytotherapy has already been described, although so far, the true incidence and the pathogenic mechanisms are largely unknown. It is important to increase awareness of both clinicians and patients about the potential dangers of herbal remedies; surveillance systems and quality control of these products are necessary.

Herbal hepatotoxicity

There is appropriate concern about the potential risk for hepatotoxicity from herbal products because they are unregulated and therefore not standardized with regard to their contents. This is particularly the case for the crude herbals that are commonly formulated as a mixture, so that their ingredients may be ambiguous and even contain harmful contaminants. Presented here is an overview of the more commonly recognized herbal products that have been reported to be associated with liver injury. Although many of them are clearly implicated, there are some, particularly those identified solely through an occasional case report, for which the relationship is uncertain.