Irritable Bowel Syndrome Score Research Articles

Efficacy of Dietary Interventions for Irritable Bowel Syndrome: A Systematic Review and Network Meta-Analysis

Introduction: Irritable bowel syndrome (IBS) is a common condition that alters the quality of life of patients. A variety of dietary interventions have been introduced to address this debilitating condition. The low-FODMAP diet (LFD), gluten-free diet (GFD), and Mediterranean diet are examples showing efficacy. The aim of this network meta-analysis was to compare these interventions to find the best approach. Methods: We performed a systematic review of the available literature through 14 March 2024 in the following databases: Embase, PubMed, MEDLINE OVID, Web of Science, CINAHL Plus, and Cochrane Central. We only included randomized controlled trials (RCTs). We used a random effects model and conducted a direct meta-analysis based on the DerSimonian–Laird approach and a network meta-analysis based on the frequentist approach. Mean differences (MDs) with 95% confidence interval (CI) were calculated. The primary outcomes included IBS quality of life (IBS QOL) and IBS symptom severity scale (IBS-SSS). Results: We finalized 23 studies including 1689 IBS patients. In the direct meta-analysis, there was no statistically significant difference in any IBS score between GFD and either LFD or standard diet. Meanwhile, the LFD was statistically superior to the standard diet in the IBS-SSS (MD: −46.29, CI: −63.72–−28.86, p < 0.01) and IBS QOL (MD: 4.06, CI: 0.72–7.41, p = 0.02). On ranking, the Mediterranean diet showed the greatest improvement in IBS-SSS, IBS-QOL, distension, dissatisfaction, and general life interference, followed by the LFD alone or in combination with the GFD. Conclusions: We demonstrated the efficacy of dietary interventions such as the LFD and Mediterranean diet in improving IBS. There is a need for large RCTs with head-to-head comparisons, particularly for the Mediterranean diet.

PHARMACOLOGIC TREATMENT OF THE IRRITABLE BOWEL SYNDROME: A COMPREHENSIVE SYSTEMATIC REVIEW

Background: Abdominal pain and changes in stool frequency are two of the symptoms of Irritable Bowel Syndrome (IBS), a chronic gastrointestinal illness. As there is no known cure, treatment focuses on symptom management. Patients struggle with psychological and emotional issues that lower their quality of life. Clinical trials have demonstrated the therapeutic effects of several therapeutic drugs, which may improve GI symptoms and general quality of life. Effective treatment of IBS requires an understanding of the connection between pharmaceutical medicines and the illness. Methods: Following PRISMA 2020 guidelines, this systematic review concentrated on full-text English literature published between 2014 and 2024. Editorials and review articles that appeared in the same journal as the submission were not accepted without a DOI. The literature was assembled using a variety of online databases, including ScienceDirect, PubMed, and SagePub. Result: The study screened about 20.000 publications using reputable sources including Science Direct, SagePub, and PubMed. Seven papers were found to be pertinent for systematic investigation, after which the entire material was examined in more detail. Conclusion: IBS treatment has shown significant improvement in patients with Minesapride, a novel 5-HT4 receptor agonist, and tenapanor. Tenapanor showed significant improvement in symptoms, treatment metrics, and satisfaction, while geraniol improved the inflammatory profile. Melatonin showed improvement in IBS score and GI symptoms, but no significant improvement in frequency of defecations per week. Amitriptyline showed effectiveness over placebo, while co-micronized PEA/PD improved IBS symptoms in children.

Effects of adherence to the Mediterranean diet in children and adolescents with irritable bowel syndrome.

BACKGROUNDIrritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder in children and adults, which increased over the past twenty years. The Mediterranean diet is a well-known diet full of antioxidants and anti-inflammatory ingredients. AIMTo evaluate the safety, tolerability, and effects of adherence to the Mediterranean diet on disease patterns in children and adolescents with IBS.METHODSThis prospective, cross-sectional case-controlled study included 100 consecutive IBS patients diagnosed according to Rome IV criteria, aged 12-18 years. Patients were subdivided into two groups (50 patients each); Group I received a Mediterranean diet, and Group II on their regular diet for six months. Besides IBS scores (IBS-SSS, IBS-QoL, and total score), different clinical and laboratory parameters were evaluated at the start and end of the study.RESULTSThe Mediterranean diet was safe and well-tolerated in IBS patients. IBS children and adolescents with good adherence to the Mediterranean diet (KIDMED Score ≥ 8 points); group I showed significant improvement in IBS scores. IBS-SSS in the Mediterranean diet group was 237.2 ± 65 at the beginning of the study and decreased to 163.2 ± 33.8 at the end of the study (P < 0.001). It did not show a significant improvement in the group with a regular diet (248.3 ± 71.1 at the beginning of the study compared to 228.5 ± 54.3 at the study end with P < 0.05). The mean IBS-SSS in the Mediterranean diet group significantly improved compared with the group with a regular diet. Mean IBS-QoL in group I improved from 57.3 ± 12.9 at the start of the study to 72.4 ± 11.2 at the study end (P < 0.001) and significantly improved when compared to its level in group II at the study end (59.2 ± 12.7 with P < 0.001), while group II showed no significant improvement in IBS-QoL at the study end when compared to the beginning of the study (59.2 ± 11.7 with P >0.05). The mean total IBS score in group I became 28.8 ± 11.2 at the end of our study compared to 24.1 ± 10.4 at the start (P < 0.05) and significantly improved when compared to its level in group II at the end of the study (22.1 ± 12.5 with P < 0.05), while in group II, non-significant improvement in the total score at the end of our study compared to its mean level at the start of the study (22.8 ± 13.5 with P > 0.05).CONCLUSIONThe Mediterranean diet was safe and associated with significant improvement in IBS scores in children and adolescent patients with IBS.

The Relationship Between Daytime Salivary Melatonin and Gastrointestinal Symptoms in Young Adults Seeking Psychiatric Care.

The pathophysiology of irritable bowel syndrome (IBS) is not completely understood, although we do know that patients with IBS have a high prevalence of psychiatric comorbidity (mainly depression and anxiety disorders). Melatonin, produced in the gastrointestinal tract, influences gut motility. Psychiatric conditions are associated with circadian disturbances in peripheral melatonin levels. This study aimed to investigate associations between daytime salivary melatonin and gastrointestinal symptoms in young adult psychiatric patients. Ninety-six patients (86% women), aged 18-25 years (M (SD) = 21 (2)), seeking psychiatric care with primarily anxiety disorders, affective disorders, or both were included in the study. Total scores from the Gastrointestinal Symptoms Rating Scale - IBS were compared with salivary melatonin measured at three time points (30 minutes after waking up, at 11:00 hours and 30 minutes after lunch) during the waking hours of 1 day. After adjustment for potential confounders, melatonin levels in saliva 30 minutes after lunch remained significantly correlated to the total Gastrointestinal Symptoms Rating Scale - IBS score after correction for multiple testing (B = 0.016, SE = 0.006, p = .015, q = 0.045). In a post hoc analysis, symptoms of gastrointestinal pain and bloating contributed most to this association. In young adult psychiatric patients, salivary melatonin levels after lunch are associated with gastrointestinal symptoms, which is consistent with the proposed effect of elevated levels of gastrointestinal melatonin on gut motility. This result suggests a link between IBS symptoms and regulation of melatonin in patients with psychiatric disorders.

Effect of a Preparation of Four Probiotics on Symptoms of Patients with Irritable Bowel Syndrome: Association with Intestinal Bacterial Overgrowth

The effect of probiotics on small intestinal bacterial overgrowth (SIBO) in irritable bowel syndrome (IBS) has never been studied so far. In this prospective trial, five patients with IBS and SIBO and 21 patients with IBS without SIBO were administered an oral capsule containing Saccharomyces boulardii, Bifidobacterium lactis, Lactobacillus acidophilus, and Lactobacillus plantarum (Lactolevure®) every 12 h for 30 days. SIBO was defined by quantitative culture of the third part of the duodenum; IBS was defined by the Rome III criteria. Severity of symptoms was graded by the IBS severity scoring system (SSS). The primary study endpoint was the efficacy of probiotics in improvement of symptoms of IBS in patients with SIBO. Thirty days after the end of treatment, a 71.3% decrease of the total IBS score was detected in patients with IBS and SIBO compared to 10.6% in those without SIBO (p 0.017). A similar decrease was achieved among patients with constipation-predominant IBS without SIBO. Post-treatment satisfaction from bowel function was greater in patients with SIBO. Similar satisfaction improvement was found among patients with diarrhea-predominant IBS irrespective from SIBO; pain intensity score decreased in patients with constipation-predominant IBS irrespective from SIBO. The benefit of probiotics was greater among patients with a pro-inflammatory cytokine pattern in the duodenal fluid. This is the first study that prospectively demonstrated superior clinical efficacy of probiotics in patients with IBS with SIBO. Analysis also showed considerable benefit from probiotic intake regarding certain symptoms of patients with diarrhea-predominant and constipation-predominant IBS.Trial registration: ClinicalTrials.gov identifier NCT02204891.

Vitamin D supplementation in adolescents with irritable bowel syndrome: Is it useful? A randomized controlled trial.

Background/Aim:Vitamin D deficiency is common in irritable bowel syndrome (IBS). There is growing interest in the role of vitamin D in pediatric IBS. We aimed to evaluate the effect of vitamin D supplementation in adolescents with IBS and vitamin D deficiency.Patients and Methods:One hundred and twelve adolescents with IBS and vitamin D deficiency were randomly divided into two groups of matched age and sex. The first group received oral vitamin D3 2000IU/day for 6 months and the second group received placebo for 6 months. Vitamin D status as well as different IBS score systems (IBS-SSS, IBS-QoL, and total score) were evaluated before and 6 months after treatment.Results:IBS patients who received vitamin D supplementation for 6 months showed significant improvement in IBS-SSS (P < 0.001), IBS-QoL (P < 0.001), and total score (P = 0.02) compared to IBS placebo group. IBS patients treated with vitamin D showed two folds increase in their serum vitamin D levels (from 17.2 ± 1.3 to 39 ± 3.3) ng/ml with P < 0.001. While in the placebo group, their serum vitamin D levels were not significantly changed (P = 0.66). Vitamin D was tolerated well without any recorded adverse effects during the study period.Conclusion:Vitamin D supplementation can be effective in treating adolescents with IBS and vitamin D deficiency.

A low fermentable oligo-di-mono saccharides and polyols (FODMAP) diet reduced pain and improved daily life in fibromyalgia patients

Background and aimsFibromyalgia (FM) is a chronic, rheumatic disease characterized by widespread myofascial pain, of unknown aetiology, having a major impact on quality of life (QOL). Available pharmacotherapy for FM is marginally effective. FM is associated with co-morbidities of gastrointestinal (GI) disorders and Irritable Bowel Syndrome (IBS). There is growing evidence that diets low in FODMAPs, “fermentable oligo-, di- or mono-saccharides and polyols” [Low FODMAP Diet (LFD)], are effective in treating IBS. The aim of this pilot study was to examine the effects of LFDs on symptoms of FM, especially with regard to pain, QOL and GI disorders. MethodsA longitudinal study using LFD intervention was performed on 38, 51±10 year-old, female patients diagnosed with FM for an average of 10 years, based on ACR (American College of Rheumatology) 2010 criteria. The study was conducted from January through May, 2015, using a four-week, repeated-assessment model, as follows: Moment 0 – introduction of the protocol to participants; Moment 1 – first assessment and delivery of individual LFD dietary plans; Moment 2 – second assessment and reintroduction of FODMAPs; Moment 3 – last assessment and final nutritional counselling. Assessment tools used were the following: RFIQ (Revised Fibromyalgia Impact Questionnaire), FSQ (Fibromyalgia Survey Questionnaire), IBS-SSS (Severity Score System), EQ-5D (Euro-QOL quality of life instrument), and VAS (Visual Analogue Scale). Daily consumption of FODMAPs was quantified based on published food content analyses. Statistical analyses included ANOVA, non-parametric Friedman, t-student and Chi-square tests, using SPSS 22 software. ResultsThe mean scores of the 38 participants at the beginning of the study were: FSQ (severity of FM, 0–31) – 22±4.4; RFIQ (0–100) – 65±17; IBS-SSS (0–500) – 275±101; and EQ-5D (0–100) – 48±19. Mean adherence to dietary regimens was 86%, confirmed by significant difference in FODMAP intakes (25g/day vs. 2.5g/day; p<0.01). Comparisons between the three moments of assessment showed significant (p<0.01) declines in scores in VAS, FSQ, and RFIQ scores, in all domains measured. An important improvement was observed with a reduction in the severity of GI symptoms, with 50% reduction in IBS scores to 138±117, following LFD therapy. A significant correlation (r=0.36; p<0.05) was found between improvements in FM impact (declined scores) and gastrointestinal scores. There was also a significant correlation (r=0.65; p<0.01) between “satisfaction with improvement” after introduction of LFDs and “diet adherence”, with satisfaction of the diet achieving 77% among participants. A significant difference was observed between patients who improved as compared to those that did not improve (Chi-square χ2=6.16; p<.05), showing that the probability of improvement, depends on the severity of the RFIQ score. ConclusionsImplementation of diet therapy involving FODMAP restrictions, in this cohort of FM patients, resulted in a significant reduction in GI disorders and FM symptoms, including pain scores. These results need to be extended in future larger studies on dietary therapy for treatment of FM. ImplicationsAccording to current scientific knowledge, these are the first relevant results found in an intervention with LFD therapy in FM and must be reproduced looking for a future dietetic approach in FM.

Randomized clinical study: Partially hydrolyzed guar gum (PHGG) versus placebo in the treatment of patients with irritable bowel syndrome.

BackgroundThe treatment of Irritable bowel syndrome (IBS) is still challenging. Partially hydrolyzed guar gum (PHGG) is a known prebiotic fiber. To assess the effects of PHGG on clinical symptoms of IBS patients in a prospective randomized double blind placebo-controlled study.MethodsSuitable IBS patients were recruited into an 18-week-long study (2 weeks of run-in, 12 weeks of treatment and 4 weeks of follow-up). They were blindly randomized to receive 6 gr of PHGG or placebo. Treatment efficacy was evaluated by the Francis Severity IBS score, the IBS quality-of-life scores and scored parameters of weekly journal of symptoms. Deltas of changes between the final and baseline scores were compared between two groups.ResultsOf 121 patients who underwent randomization, 108 patients (49 in the PHGG group and 59 in the placebo group) had all the data needed for intention-to-treat analysis. A 12-week administration of PHGG led to a significant improvement of journal bloating score in the PHGG group versus placebo (−4.1±13.4 versus −1.2±11.9, P=0.03), as well as in bloating+gasses score (−4.3±10.4 versus −1.12±10.5, P = 0.035). The effect lasted for at least 4 weeks after the last PHGG administration. PHGG had no effect on other journal reported IBS symptoms or on Severity and Quality of life scores. There were no significant side effects associated with PHGG ingestion. The rate of dropouts was significantly higher among patients in the placebo group compared with the PHGG group (49.15% versus 22.45%, respectively, P = 0.01).ConclusionsThe results of this study support the administration of 6 g/day PHGG for IBS patients with bloating.Trial registrationNCT01779765

Clinical observation of diarrhea type irritable bowel syndrome with Shugan Jianpi prescription

Objective To discuss the clinical observation of diarrhea type irritable bowel syndrome with Shugan Jianpi prescription. Methods 82 cases of diarrhea- predominant irritable bowel syndrome were selected using a random number table,the observation group(n= 45) was treated with relieving liver and reinforcing spleen methods; the control group(n= 37)was treated with the universal application of clinical Pinaverium bromide, were observed after treatment of irritable bowel syndrome score, treatment effects as well as the clinical symptoms, the results were processed using SPSS 17.0 analysis. Results The scores of the two groups at 1 month after treatment, the control group was(157.38±72.72), the observation group was(101.52±60.16)(t=- 7.994,P= 0.000). The score of the two groups at 3 months after treatment, the control group was(172.71±62.91), the observation group was(109.92±42.38)(t=- 8.428,P= 0.000), the results had statistical significance; The total efficiency of the two groups at 1 month after treatment, the control group was 75.7%, the observation group was 95.6%(χ2= 6.909,P= 0.019), the total efficiency of the two groups at 3 months after treatment,the control group was 86.5%,the observation group was 100%,the comparison was(χ2= 6.476,P= 0.016),the results had statistical significance.On the aspect of the relieve of clinical symptoms, On the abdominal pain, the control group controlled 21cases,the observation group controlled 38 cases, compared (χ2= 7.713,P= 0.007), On the diarrhea,the control group relieved 15 cases,the observation group relieved 30 cases,compared(χ2= 7.713,P= 0.007),both had statistical significance. Conclusion The methods with relieving liver and reinforcing spleen, to the patients with irritable bowel syndrome medicine syndrome differentiation, play each medicine spleen and stomach, benefit lung and kidney tonic win effect, can effectively reduce symptoms and reduce IBSintegration,reduce symptoms treatment results. Key words: Irritable bowel syndrome; Shuganjianpi France; Pinaverium bromide

Semiquantitative fecal calprotectin test in postinfectious and non-postinfectious irritable bowel syndrome: cross-sectional study.

The presence of a certain degree of inflammation in the gut wall is now accepted in irritable bowel syndrome (IBS). Fecal calprotectin is considered to be a reliable test for detecting intestinal inflammation. Our aim was to assess the presence of inflammation in postinfectious IBS (PI-IBS), compared with non-postinfectious IBS (NPI-IBS). A secondary objective was to determine the usefulness of a rapid fecal calprotectin test in inflammatory bowel diseases (IBD). This was a cross-sectional study. Patients with IBS and IBD at a single tertiary gastroenterology center were prospectively included in this study. 116 patients with Rome III IBS score (76 females; 48 ± 12 years) were investigated; 24 patients (15 females) had PI-IBS. Intestinal inflammation was assessed using the semiquantitative fecal calprotectin test. The results were expressed as T1, T2 or T3 according to the severity of inflammation (< 15 μg/g; 15-60 μg/g; > 60 μg/g). Using the same test, we evaluated 20 patients with IBD (12 males; 47 ± 13 years). None of the patients with IBS had a T2 or T3 positive test. Among PI-IBS patients, 33% had a T1 positive test. Among NPI-IBS patients, 9.8% had a T1 positive test, which was significantly different to PI-IBS. The calprotectin test was positive in all IBD patients: 80% with T3, 10% with T2 and 10% with T1. Using a semiquantitative test for fecal calprotectin, positive tests were more frequent in PI-IBS patients than in NPI-IBS patients.

Partially hydrolyzed guar gum in pediatric functional abdominal pain

To assess the effects of partially hydrolyzed guar gum (PHGG) diet supplement in pediatric chronic abdominal pain (CAP) and irritable bowel syndrome (IBS). A randomized, double-blind pilot study was performed in sixty children (8-16 years) with functional bowel disorders, such as CAP or IBS, diagnosed according to Rome III criteria. All patients underwent ultrasound, blood and stool examinations to rule out any organic disease. Patients were allocated to receive PHGG at dosage of 5 g/d (n = 30) or placebo (fruit-juice n = 30) for 4 wk. The evaluation of the efficacy of fiber supplement included IBS symptom severity score (Birmingham IBS Questionnaire), severity of abdominal pain (Wong-Baker Face Pain Rating Score) and bowel habit (Bristol Stool Scale). Symptom scores were completed at 2, 4, and 8 wk. The change from baseline in the symptom severity scale at the end of treatment and at 4 wk follow-up after treatment was the primary endpoint. The secondary endpoint was to evaluate compliance to supplementation with the PHGG in the pediatric population. Differences within groups during the treatment period and follow-up were evaluated by the Wilcoxon signed-rank test. The results of the study were assessed considering some variables, such as frequency and intensity of symptoms with modifications of the bowel habit. Both groups were balanced for baseline characteristics and all patients completed the study. Group A (PHGG group) presented a higher level of efficacy compared to group B (control group), (43% vs 5%, P = 0.025) in reducing clinical symptoms with modification of Birmingham IBS score (median 0 ± 1 vs 4 ± 1, P = 0.025), in intensity of CAP assessed with the Wong-Baker Face Pain Rating Score and in normalization of bowel habit evaluated with the Bristol Stool Scale (40% vs 13.3%, P = 0.025). In IBS subgroups, statistical analysis shown a tendency toward normalization of bowel movements, but there was no difference in the prevalence of improvement in two bowel habit subsets. PHGG was therefore better tolerated without any adverse effects. Although the cause of pediatric functional gastrointestinal disorders is not known, the results show that complementary therapy with PHGG may have beneficial effects on symptom control.

The efficacy of probiotics in the treatment of irritable bowel syndrome: a systematic review

IntroductionProbiotics may benefit irritable bowel syndrome (IBS) symptoms, but randomised controlled trials (RCTs) have been conflicting; therefore a systematic review was conducted.MethodsMEDLINE (1966 to May 2008), EMBASE (1988 to May...

High Prevalence of Irritable Bowel Syndrome in Medical Outpatients in Japan

The prevalence of irritable bowel syndrome (IBS) among Japanese patients who visit hospitals departments of internal medicine is thought to be high. However, no clear statistical evidence has been provided to support such a claim. We tested the hypotheses that the prevalence of IBS in medical outpatients clinics in Japan is high, and that IBS patients feel more psychosocial stress than patients without IBS. The subjects in this study were 633 patients who visited participating physicians. Patients were asked to fill in the Japanese version of the Rome II Modular Questionnaire (RIIMQ) for IBS diagnosis, the Self-reported Irritable Bowel Syndrome Questionnaire (SIBSQ) for severity of the disease and the demographic questionnaire for perceived stress and life style. Rome II-defined IBS was diagnosed in 196 patients (31%). Analysis of variance revealed significant difference in the IBS scores of SIBSQ among IBS subjects (39.0+/-11.1, mean+/-SD), functional bowel disorder subjects (27.1+/-10.2), and normal subjects (24.0+/-10.0, P<0.01). The prevalence of IBS depending on age formed 2 peaks, one among adolescents and the other among the elderly. IBS patients had significantly more perceived stress (P<0.0001), irregular sleep habit (P<0.0001), and irregular meal habit (P<0.0001) than those without IBS. The prevalence of IBS among medical outpatients in Japan is high (31%). IBS subjects among medically ill patients are thought to have more perceived stress and less regular life styles.

Clinical Trial on the Efficacy of a New Symbiotic Formulation, Flortec, in Patients With Irritable Bowel Syndrome

Efficacy of symbiotics in patients with irritable bowel syndrome (IBS) remains unknown. Patients were randomized to a prebiotic (n=135), or a symbiotic formulation containing Lactobacillus paracasei B21060 (Flortec, n=132). Primary efficacy was the responder rate for pain and global relief of symptoms in the overall population and in patients with predominant diarrhea (n=47). Post hoc time-trend analyses for changes within each treatment were carried out. Patients with absent/mild pain amounted to 54.7% in the symbiotic group and to 57.4% in the prebiotic group at treatment week 4, and to 53.9% and 53.4% at the end of treatment. Patients with amelioration of well-being were, respectively, 60.7% versus 61.7% at treatment week 4, and 63.3% versus 60.9% at the end of treatment. Within each treatment group, patients with absent/mild pain increased in the Flortec and the prebiotic group, but time trend analyses were significant only for Flortec (P=0.019). In IBS-predominant diarrhea, Flortec significantly reduced bowel movements, pain, and IBS scores. To improve pain and well-being, Flortec is encouraging in patients with diarrhea predominant IBS. To establish its efficacy for the majority of IBS patients, Flortec has to be compared with an inert placebo in future work.

A Preliminary Study of Melatonin in Irritable Bowel Syndrome

Melatonin is involved in the regulation of gut motility and sensation. We aimed to determine if melatonin was effective in improving bowel symptoms, extracolonic symptoms, and quality of life (QOL) in irritable bowel syndrome (IBS) patients. Eighteen patients (aged 18 to 65 y; 6 females) were randomly assigned to receive either melatonin 3 mg (n=9) or matching placebo (n=9) at bed time for 8 weeks. The overall IBS scores, extracolonic IBS scores, QOL scores were assessed at 2, 4, 6, and 8 weeks during treatment and at 16, 24, and 48 weeks during follow up. Compared with placebo, melatonin taken for 8 weeks significantly improved overall IBS score (45% vs. 16.66%, P<0.05). The posttreatment overall extracolonic IBS score was significantly lower (49.16% to 13.88%, P<0.05) when compared with placebo group. The overall improvement in QOL score was 43.63% in melatonin group and 14.64% in placebo group that is statistically significant. The result of this study showed that melatonin has some beneficial role in IBS. Further studies using large number of patients may provide a definite answer.

Melatonin improves bowel symptoms in female patients with irritable bowel syndrome: a double‐blind placebo‐controlled study

Melatonin is involved in the regulation of gastrointestinal motility and sensation. To determine the potential therapeutic effects of melatonin in irritable bowel syndrome (IBS). Seventeen female patients satisfying the Rome II criteria for IBS were randomized to receive either melatonin 3 mg nocte or identically appearing placebo 1 nocte for 8 weeks, followed by a 4-week washout period and placebo or melatonin in the reverse order for another 8 weeks. Three validated questionnaires - the GI symptom, the sleep questionnaires and the Hospital Anxiety and Depression Scale - were used to assess symptom severity and to compute the IBS, sleep and anxiety/depression scores, respectively. Improvements in mean IBS scores were significantly greater after treatment with melatonin (3.9 +/- 2.6) than with placebo (1.3 +/- 4.0, P = 0.037). Percent response rate, defined as percentage of subjects achieving mild-to-excellent improvement in IBS symptoms, was also greater in the melatonin-treated arm (88% vs. 47%, P = 0.04). The changes in mean sleep, anxiety, and depression scores were similar with either melatonin or placebo treatment. Melatonin is a promising therapeutic agent for IBS. Its therapeutic effect is independent of its effects on sleep, anxiety or depression.