Improvement in irritable bowel syndrome following ano-rectal surgery

BACKGROUND AND AIMS

To assess the effect on irritable bowel syndrome (IBS) of treating ano-rectal problems by applying multiple Barron's bands to prolapsing mucosa and excising haemorrhoids, with or without a low lateral sphincterotomy.

PATIENTS AND METHODS

144 patients with IBS whose ano-rectal abnormalities were treated by a single consultant surgeon. A prospective "within person" study of consecutive patients referred with ano-rectal problems who also had IBS symptoms according to the Rome criteria. All patients completed structured questionnaires about anal and IBS symptoms before operation and 6-60 months later. The findings were compared with those from patients who had no abdominal pains.

RESULTS

The principal IBS symptoms of abdominal pain, abdominal distension, and altered bowel habit all improved significantly after operation. Those with persistent anal problems had more problems with persistent IBS symptoms, but when the anal problems were corrected, the IBS tended to settle. Posterior anal tenderness is present in 80% of IBS patients and is a useful diagnostic sign.

CONCLUSIONS

This work suggests that in many patients with IBS there is a physical ano-rectal disorder amenable to physical treatment. Patients with IBS should all be proctoscoped carefully, with and without the patient straining, looking for abnormalities. Correcting mucosal prolapse and other anal problems produced an improvement in IBS symptoms in 86% of patients. This suggests that ano-enteric reflexes are a significant factor in irritable bowel syndrome, if not the major cause.

Behavioral and physiological sleep characteristics in women with irritable bowel syndrome

OBJECTIVES

The goal of this study was to investigate behavioral (self-reported) and physiological sleep characteristics in irritable bowel syndrome (IBS) patients with and without concurrent dyspeptic symptoms, as compared to control subjects.

METHODS

A total of 31 women with IBS were stratified into two groups: 15 with bowel symptoms only (IBS-only) and 16 with both lower and upper dyspeptic symptoms (IBS+D). In addition, 23 healthy women served as controls. For 4 consecutive days, subjective sleep quality, insomnia symptoms, alertness, state anxiety, perceived daytime stress, and daytime and nighttime GI symptoms were assessed. On night 4, subjects underwent polysomnographic (PSG) monitoring for an objective assessment of sleep quality including microarousals and respiratory parameters. Saliva samples were collected for cortisol analyses each morning and evening across the 4 days of the study. Psychological disturbances were assessed with the SCL.

RESULTS

Patients reported significantly more dissatisfaction with their sleep quality and increased daytime fatigue as a result of both insomnia-type symptomatology and nonrestful sleep. These complaints were significantly greater in IBS+D compared to IBS-only for some measures. A significant proportion of patients, particularly IBS+D patients, reported nighttime GI symptoms. Patients reported significantly greater average anxiety across the 4 days, which was greatest in IBS+D. Although both patient subgroups showed normal levels and circadian changes in cortisol compared to controls, IBS+D had significantly increased morning salivary cortisol levels compared to IBS-only. PSG data showed no significant differences between the patient groups and controls. Significant correlations were found between psychological distress and retrospective subjective sleep complaints for patients.

CONCLUSIONS

This study confirms the importance of sleep complaints and nighttime GI symptoms in women with IBS that are not substantiated by any objective, physiological evidence. Rather, there is a reporting bias regarding sleep disturbances, which appears to be related to symptom severity and psychological disturbances.

Prognosis in post-infective irritable bowel syndrome: a six year follow up study

BACKGROUND

Irritable bowel syndrome developing following infective gastroenteritis accounts for approximately 1 in 10 of unselected IBS patients.

AIMS

To define the long term natural history of post-infective IBS (PI-IBS).

METHODS

A total of 436 individuals, who had previously responded to a questionnaire on their bowel habits following an acute episode of gastroenteritis, were sent a questionnaire about their current bowel habits and physical and mental health six years after their initial illness.

RESULTS

Complete data on original bowel habit, episodes of gastroenteritis, mental health history, and subsequent bowel habit at six years were obtained in 192 individuals. Of these, there were 14 cases of "post-infective IBS" (PI-IBS) and 13 who had IBS prior to infection (previous IBS). Over the six year follow up period there were 20 "new non-infective IBS cases" (new IBS). The strongest risk factor for developing any type of IBS was female sex (relative risk 2.2, p<0.05). Compared with new IBS, those with PI-IBS had significantly more days with loose stools (p<0.05) but a similar number of days with pain, urgency, and bloating. Six of 14 (43%) PI-IBS and four of 13 (31%) previous IBS patients recovered by six years (NS). Of 27 IBS patients followed for six years, only 1/8 with a history of anxiety or depression recovered compared with 9/19 without such a history (p=0.19).

CONCLUSION

PI-IBS differs from non-infective IBS by having more diarrhoeal features. Less than half of both PI-IBS and non-infective IBS cases recover over six years. A history of anxiety and depression severe enough to warrant treatment may impair recovery but larger numbers are needed to prove this.

Lipid-induced intestinal gas retention in irritable bowel syndrome

BACKGROUND & AIMS

We hypothesized that lipids, which induce various motor and sensory effects on the gut, modulate intestinal gas dynamics and that alteration of this regulatory mechanism may result in impaired gas transit in patients with irritable bowel syndrome (IBS).

METHODS

In 45 healthy subjects and 30 patients with IBS, evacuation of gas infused into the jejunum (at 12 mL/min) was measured for 2 hours. The effect of simultaneous duodenal perfusion of lipids at 0 kcal/min (saline), 0.5 kcal/min, and 1 kcal/min was tested in groups of 15 subjects each.

RESULTS

In healthy subjects, duodenal lipids at 1 kcal/min but not at 0 kcal/min or 0.5 kcal/min produced significant gas retention (281 +/- 53 mL vs. 22 +/- 64 mL at 0 kcal/min and -65 +/- 72 mL at 0.5 kcal/min; P < 0.05 for both). Patients with IBS exhibited gas retention during saline perfusion (259 +/- 85 mL at 0 kcal/min; P < 0.05 vs. healthy subjects) and were hypersensitive to duodenal lipids (505 +/- 61 mL retention at 0.5 kcal/min; P < 0.05 vs. saline and vs. healthy subjects). The "gas plus lipids" challenge test discriminated patients with 100% sensitivity and 93% specificity.

CONCLUSIONS

Physiologic concentrations of intestinal lipids exert an inhibitory control on intestinal gas transit, and this mechanism is up-regulated in patients with IBS. Hence, impaired gas propulsion, shown by the gas challenge test, may be useful as a diagnostic test if replicated in a larger series of patients.

Tegaserod, a 5-hydroxytryptamine type 4 receptor partial agonist, is devoid of electrocardiographic effects

OBJECTIVES

Certain GI prokinetic agents have been shown to affect cardiac repolarization, which may be associated with life-threatening arrhythmias. The selective 5-hydroxytryptamine type 4 receptor partial agonist tegaserod is a novel promotile agent developed for the treatment of functional motility disorders such as irritable bowel syndrome (IBS). The aim of the study was to investigate the cardiac safety profile of tegaserod through analysis of electrocardiographic data from clinical studies conducted in patients with IBS and a study conducted in healthy male subjects.

METHODS

In three randomized, double blind, placebo-controlled, parallel group clinical studies, 2516 IBS patients with symptoms of abdominal pain and constipation received tegaserod 2 or 6 mg b.i.d. (n = 1679) or placebo (n = 837) for 12 wk. In an additional study, 36 healthy male subjects received iv. single doses of tegaserod (0.8 mg to 20 mg) or placebo. Standard 12-lead electrocardiograms were recorded at baseline and during treatment. Baseline values were compared with data collected during the treatment period.

RESULTS

The proportion of patients with prolongation of the QTc interval was the same for placebo and tegaserod, as was the frequency of overall electrocardiographic abnormalities. No ventricular or supraventricular tachycardia was observed. Comparable electrocardiographic results were obtained during placebo and tegaserod treatment. In healthy volunteers, tegaserod at i.v. doses resulting in plasma concentrations up to 100 times those measured after therapeutic doses (6 mg b.i.d.) did not influence electrocardiographic parameters.

CONCLUSIONS

Tegaserod is devoid of electrocardiographic effects and is not expected to adversely influence cardiac function. These data confirm preclinical findings.

Effect of red chillies on small bowel and colonic transit and rectal sensitivity in men with irritable bowel syndrome

BACKGROUND

Altered motility and threshold for pain have been incriminated in the pathogenesis of the irritable bowel syndrome (IBS). Capsaicin affects visceral sensory perception and chillies, which contain capsaicin, have been shown to accelerate gut transit.

AIMS

To evaluate the effect of red chillies on small bowel transit (SBT) and colonic transit (CT) and rectal sensitivity in normal men and men with IBS.

METHODS

Twenty-nine men with IBS diagnosed using Manning's criteria, and 21 healthy men, were studied before and after ingestion of 10 g red chilli powder (capsaicin equivalent 14 mg). SBT time was measured as the time taken for 99mTc-sulfur colloid to reach the cecum after leaving the stomach. Total and segmental CT times were assessed using radio-opaque markers. Rectal sensitivity and pain threshold to intrarectal balloon distension were measured.

RESULTS

The median (range) bowel frequency in patients and healthy men was 2 (1-6) and 1 (1-3) per day (p=0.03), respectively. After ingestion of chillies, it increased to 3 (1-8) per day and 2 (1-4) per day (p=0.01), respectively. There was no difference in transit times between patients and healthy men; chilli ingestion did not alter SBT time, total or segmental CT time. IBS patients had a lower threshold to balloon distension for both discomfort and pain in the basal state (p<0.01). Chillies increased this threshold in healthy men (p<0.01).

CONCLUSIONS

Men with IBS do not have SBT or CT abnormalities, but have a lower rectal balloon sensitivity threshold. Chilli powder does not alter either SBT or CT in men with IBS or healthy men; however, it increases the rectal threshold for pain in the latter.

Abnormalities of GI transit in bloated irritable bowel syndrome: effect of bran on transit and symptoms

OBJECTIVES

Bloating is an important but poorly understood symptom in irritable bowel syndrome (IBS) that is often aggravated by bran. The aim of our study was to determine whether IBS patients with bloating responded to bran differently from healthy controls.

METHODS

A total of 12 patients with IBS (according to Rome I criteria), all with moderate to severe bloating, and 12 healthy controls participated in a two way, double blind, randomized, cross-over trial of bran versus placebo (crushed biscuits) 15 g b.i.d. An average daily pain index and bloating score were derived from daily symptom diaries. On day 14, gastric emptying, small bowel transit, percent remaining in ascending colon, and geometric center of a meal marker at 24 h were calculated from scintigraphic images obtained after ingesting a Tc99m-labeled rice pudding meal with 15 g of either placebo or coarse bran.

RESULTS

Results are given as median (range). Bran significantly increased the pain index and bloating (p < 0.02) in IBS patients but not controls. The most striking finding was that the small bowel transit time of the meal without bran was markedly faster in IBS patients than in controls, being 203 min (range 109-313) versus 367 min (219-543), p < 0.001. Although in controls bran accelerated small bowel transit time to 262 min (180-380), p = 0.03, and significantly reduced % remaining in the ascending colon from 22% (0-46) to 3% (0-25), p = 0.03, this was not seen in the IBS patients. Bran accelerated whole gut transit as assessed by geometric center at 24 h in both IBS patients and controls.

CONCLUSIONS

Bran accelerates small bowel transit and ascending colon clearance without causing symptoms in controls. Small bowel transit is rapid in IBS patients with bloating and, unlike in healthy control subjects, cannot be further accelerated by bran, which nevertheless aggravates symptoms of pain and bloating. We speculate that bran-induced bloating may originate in the colon rather than the small bowel.

Dyspepsia, irritable bowel syndrome, and constipation: review and what's new

Functional gastrointestinal disorders are collections of symptoms attributable to the gastrointestinal tract in the absence of mucosal, structural, or biochemical disease. The two most common disorders, irritable bowel syndrome and functional dyspepsia, have common etiopathogenetic features, notably psychosocial disturbances, dysmotility, heightened sensitivity, and, possibly, an association with a postinfective state. The third condition is constipation, in which transit disorders and abnormal evacuation represent disturbances of function that are amenable to therapy. This review is an update of the control mechanisms, pathophysiology, investigation, and potential pharmacotherapies of these disorders. Serotonergic and adrenergic agents and neurotrophic factors are among the novel approaches that may have a significant impact on these disorders.

Irritable bowel syndrome: a little understood organic bowel disease?

Irritable bowel syndrome affects 10% of adults with an unexplained female predominance. Although only a few people see their family doctor, the disease causes reduced quality of life and represents a multi-billion pound health-care problem. The disorder clusters in families, which is possibly because of intra-familial learning and a genetic predisposition. Visceral hypersensitivity is a key feature in most patients. Results of imaging studies of regional cerebral blood flow during rectal distension suggest underlying disturbances of central processing of afferent signals, though this is not unique to the disorder, since it is seen in other chronic pain syndromes. Environmental factors that are strongly implicated in at least some patients include gastrointestinal infection and inflammation and chronic stress. Diagnosis is based on positive symptoms and absence of any alarm indicators. Treatment remains unsatisfactory and hinges on an excellent doctor-patient relationship, with drugs for symptom exacerbations. Cognitive behavioural treatment, psychotherapy, and hypnosis could provide long-lasting benefit in some patients. Tricyclic antidepressants in low doses seem to be the most effective class of drugs for the disorder on the basis of limited data.

Evidence for autonomic dysregulation in the irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder characterized by chronic abdominal pain and visceral hypersensitivity. In this study, resting blood pressure and heart rate were recorded in 20 IBS patients and 23 controls. We assessed pain intensity and unpleasantness to visceral and cutaneous stimuli using rectal distension and immersion of the foot in hot water. Mean resting heart rate was higher in IBS patients compared to controls. IBS patients rated pain intensity and unpleasantness to visceral and cutaneous stimuli significantly higher than controls. In IBS patients, blood pressure was significantly inversely associated with visceral pain and only weakly and positively associated with cutaneous pain; there were no relationships in controls. Sex and anxiety did not explain these relationships. In conclusion, we found evidence suggestive of central autonomic dysregulation in IBS patients.

High-fiber diet supplementation in patients with irritable bowel syndrome (IBS): a multicenter, randomized, open trial comparison between wheat bran diet and partially hydrolyzed guar gum (PHGG)

High-fiber diet supplementation is commonly used in IBS, although it poses several management problems. Partially hydrolyzed guar gum (PHGG) has shown beneficial effects in animal and human studies, but its potential role in IBS symptom relief has not been evaluated yet. We investigated PHGG in IBS patients and compared it to a wheat bran diet. Abdominal pain, bowel habits, and subjective overall rating were longitudinally evaluated in 188 adult IBS patients (139 women and 49 men) for 12 weeks. Patients were classified as having diarrhea-predominant, constipation-predominant, or changeable bowel habits and were randomly assigned to groups receiving fiber (30 g/day of wheat bran) or PHGG (5 g/day). After four weeks, patients were allowed to switch group, depending on their subjective evaluation of their symptoms. Significantly more patients switched from fiber to PHGG (49.9%) than from PHGG to fiber (10.9%) at four weeks. Per protocol analysis showed that both fiber and PHGG were effective in improving pain and bowel habits, but no difference was found between the two groups. Conversely, intention-to-treat analysis showed a significantly greater success in the PHGG group (60%) than in the fiber group (40%). Moreover, significantly more patients in the PHGG group reported a greater subjective improvement than those in the Fiber group. In conclusion, improvements in core IBS symptoms (abdominal pain and bowel habits) were observed with both bran and PHGG, but the latter was better tolerated and preferred by patients, revealing a higher probability of success than bran and a lower probability of patients abandoning the prescribed regimen, suggesting that it can increase the benefits deriving from fiber intake in IBS, making it a valid option to consider for high-fiber diet supplementation.

Tegaserod: a new 5-HT(4) agonist in the treatment of irritable bowel syndrome

Tegaserod is a selective partial agonist acting on serotonergic type 4 receptors (5-HT(4)). Pharmacodynamic studies indicate that tegaserod is able to stimulate gut propulsion and secretion with a net prokinetic effect. In contrast to other 5-HT(4) agonists endowed with a complex pharmacological profile, tegaserod has a reliable prokinetic activity in the colon. Clinical trials show that tegaserod is effective and safe in the treatment of patients with irritable bowel syndrome. In particular, tegaserod relieves symptoms of abdominal pain, discomfort, abdominal bloating and constipation.

Irritable bowel syndrome as a common precipitant of central sensitization

Animal models of neuropathic pain have significantly advanced our knowledge of abnormalities in central pain processing mechanisms in chronic pain disorders. New neuroimaging techniques using functional magnetic resonance imaging and positron emission tomography scanning are beginning to provide insight into cortical participation in the processing of pain. Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders seen by physicians. Visceral hypersensitivity or decreased pain thresholds to distension of the gut is considered to be a biologic marker for IBS and is present in most patients with this gastrointestinal disorder. Patients with IBS also have many extraintestinal symptoms consistent with a central hyperalgesic state. Recent studies suggest that patients with IBS may also have cutaneous hyperalgesia similar to that seen in other chronic pain disorders such as fibromyalgia. This suggests that abnormalities of central nociceptive processing are present in IBS.

Irritable bowel syndrome, anxiety, and depression: what are the links?

Irritable bowel syndrome (IBS) is a common and potentially disabling functional gastrointestinal disorder characterized by abdominal pain and altered bowel patterns. A significant amount of clinical and research data suggest the importance of the brain-gut interaction in IBS. This review examines the observed high prevalence of psychiatric disorders in patients with IBS. The published literature indicates that fewer than half of individuals with IBS seek treatment for it. Of those who do, 50% to 90% have psychiatric disorders, including panic disorder, generalized anxiety disorder, social phobia, posttraumatic stress disorder, and major depression, while those who do not seek treatment tend to be psychologically normal. Both physiologic and psychosocial variables appear to play important roles in the development and maintenance of IBS. Recent information suggests that the association of IBS and psychiatric disorders may be more fundamental than was previously believed. A brain-gut model for IBS is presented, and the role of traumatic stress and corticotropin-releasing factor as modulators of the brain-gut loop is discussed. Finally, the rationale for the use of psychotropic agents in the treatment of IBS with or without psychiatric symptoms is presented.

The effect of the 5-HT3 receptor antagonist, alosetron, on brain responses to visceral stimulation in irritable bowel syndrome patients

AIM

To conduct a placebo-controlled functional brain imaging study to assess the effect of the 5-hydroxytryptamine-3 receptor antagonist, alosetron, on irritable bowel syndrome symptoms, regional brain activation by rectosigmoid distension and associated perceptual and emotional responses.

METHODS

Fifty-two non-constipated irritable bowel syndrome patients (28 female) were enrolled in a randomized, placebo-controlled trial with alosetron (1-4 mg b.d.). Thirty-seven patients completed both brain scans following randomization. Rectosigmoid stimulation was performed with a computer-controlled barostat. Changes in regional cerebral blood flow were assessed using H215O positron emission tomography. Stimulus ratings and changes in gastrointestinal symptoms were assessed using verbal descriptor scales.

RESULTS

Alosetron, but not placebo, treatment was associated with a decrease in symptom ratings, and reductions in emotional stimulus ratings. Compared to baseline, alosetron treatment was associated with reduced regional cerebral blood flow in bilateral frontotemporal and various limbic structures, including the amygdala. Compared to placebo, decreases in activity of the amygdala, ventral striatum, hypothalamus and infragenual cingulate gyrus were significantly greater after alosetron.

CONCLUSIONS

In non-constipated irritable bowel syndrome patients, 3 weeks of treatment with a 5-hydroxytryptamine-3 receptor antagonist decreases brain activity in response to unanticipated, anticipated and delivered aversive rectal stimuli in structures of the emotional motor system, and this is associated with a decrease in gastrointestinal symptoms.

Neuropathophysiology of irritable bowel syndrome

Widespread symptoms associated with the irritable bowel syndrome (IBS) are abnormal defecation and abdominal pain, both of which can be exacerbated by psychogenic stress. Disordered defecation may present as diarrhea or constipation. A subgroup of IBS patients alternate from one to the other over time. Urgency to stool often accompanies the diarrheal-state, and patients with the constipation-predominant form of IBS report straining and the feeling of incomplete evacuation. Basic scientific research aims for improved understanding of the physiology and pathophysiology of the digestive systems from which the arrays of IBS symptoms emerge. The key systems for the defecation-related symptoms are the intestinal secretory glands, the musculature, and the nervous system that controls and integrates their activity. Abdominal pain and discomfort arising from these systems adds the dimension of sensory neurophysiology. This review details current concepts of the underlying pathophysiology in terms of the physiology of intestinal secretion, motility, nervous control, sensing function, immuno-neural communication, and the brain-gut axis.

Role of visceral sensitivity in the pathophysiology of irritable bowel syndrome

Visceral hypersensitivity has been recognised as a characteristic of patients with irritable bowel syndrome (IBS). It may be involved in the pathogenesis of abdominal pain/discomfort, and seems to result from the sensitisation of nerve afferent pathways originating from the gastrointestinal tract. From a clinical point of view, hypersensitivity, although frequent, is not a constant finding among patients with IBS and cannot therefore be considered as a diagnostic marker of the condition. The advances made in understanding visceral hypersensitivity in patients with IBS are reviewed: the factors that influence abdominal distension are defined and different therapeutic perspectives are examined.

Centrally acting agents and visceral sensitivity

The evidence relating to the site and mechanism of action of "centrally acting" agents which may affect visceral sensitivity is reviewed. Antidepressant drugs such as amitriptyline as well as the newer selective serotonin reuptake inhibitors are thought to act at the level of the CNS. Opiates, including morphine as well as compounds such as trimebutine or fedotozine designed for therapeutic use in irritable bowel syndrome, are effective in reducing visceral nociception. Cytokines in the CNS are known to be involved in the modulation of pain and there is also evidence to suggest that centrally acting cytokines may play a role in the production of visceral hypersensitivity. Consequently, they may provide an interesting target for future research.

Sensation and gas dynamics in functional gastrointestinal disorders

Our current knowledge of motor and sensory functions in the human gut is critically reviewed, showing how the two may interact to produce symptoms in patients with functional gastrointestinal disorders. A local stimulus is necessary to activate the pathogenetic symptom generation process, and in many patients abnormal pooling of gas at various or extensive sites in the bowel and focal gut distension may provide the local stimulus, compounded by spatial summation phenomena and conscious visceral hypersensitivity. The interplay of these mechanisms results in the clinical expression of symptoms.

Evolving concepts in the pathophysiology of functional gastrointestinal disorder

Functional gastrointestinal disorder (FGID) is common and may affect any part of the digestive tract from the esophagus to the rectum. Functional dyspepsia and the irritable bowel syndrome (IBS) are the most commonly recognized and until recently were considered distinct entities. In recent years, however, new observations and studies of the afferent nervous system have extended our concepts of both IBS and dyspepsia and suggest that these conditions may have common triggers and expression from similar pathophysiological processes.

Visceral perception: inflammatory and non-inflammatory mediators

Visceral hypersensitivity is currently the most widely accepted mechanism responsible for abdominal pain. Inflammatory mediators are known to sensitise primary afferents and to recruit silent nociceptors. Recent evidence suggests that non-inflammatory mediators also have the potential to trigger visceral pain. This sequence of events may constitute part of an alerting system which prompts the central nervous system to correct gastrointestinal responses to ingestion.

Hypersensitivity in functional gastrointestinal disorders

Patients with functional gastrointestinal disorders may have visceral sensory dysfunction so that physiological stimuli induce their symptoms. The clinical significance of altered perception-that is, its relation to clinical symptoms-remains unclear. Data indicate that sensory dysfunction is associated with altered reflex activity. Hence evidence of combined sensory-reflex dysfunction as a common pathophysiological mechanism in various functional gastrointestinal disorders would suggest that they are different forms of the same process. Altered reflex activity and altered conscious perception of gastrointestinal stimuli may combine to differing degrees, and their interaction may produce clinical symptoms.

Role of the brain and sensory pathways in gastrointestinal sensory disorders in humans

Several features of the irritable bowel syndrome (IBS) suggest involvement of the emotional limbic system in the brain. Abnormalities which upregulate afferent (sensory) signal intensity anywhere in this system, from the gastrointestinal tract to the brain, could induce hypersensitivity, leading to the pain and discomfort that characterise IBS and other functional disorders. Functional gastrointestinal disorders are likely to be heterogeneous given the complexity of the afferent system, and a number of different perturbations are possible. Intestinal hypersensitivity to pain and discomfort and associated reflex alterations in motility might explain the symptoms of functional bowel diseases.

Diet in the irritable bowel syndrome

Patients with irritable bowel syndrome (IBS) often request dietary recommendations. They must eat, and they want to know what to eat. Present national guidelines recommend dietary treatment with fiber for IBS patients with constipation. Diet recommendations are made based on symptoms. There may be different dietary recommendations for constipation, diarrhea, and pain or bloating. This article reviews the relationship of foods to IBS and issues of food intolerances and hypersensitivities, and recommendations for diet therapy. The role of dietary fiber, both soluble and insoluble, is reviewed. Although there are few studies to substantiate exact diets, broad dietary plans are recommended for the different symptoms of IBS. In addition, the recent literature on probiotics and prebiotics pertinent to IBS is reviewed.