Evidence-Based Answers

Evidence Central™ is an integrated web and mobile solution that helps clinicians quickly answer etiology, diagnosis, treatment, and prognosis questions using the latest evidence-based research.


Evidence Central for Mobile Devices

Evidence Central iOS iPhone iPad Android

Evidence Central from Unbound Medicine, available for iOS® and Android™, is optimized for each platform and features superior navigation, so answers are easy to find at the bedside or anywhere they’re needed. Learn More

Word of the Day

Probiotics somewhat helpful for IBS

Clinical Question:
Are probiotics effective for the treatment of irritable bowel syndrome?

Bottom Line:
Probiotics appear to provide small to moderate benefit for patients with irritable bowel syndrome (IBS). (LOE = 1a)

Moayyedi P, Ford AC, Talley NJ, et al.The efficacy of probiotics in the treatment of irritable bowel syndrome: a systematic review. Gut 2010;59(3):325-332.  [PMID:19091823]

Study Design:
Meta-analysis (randomized controlled trials)


Outpatient (any)

These authors identified 18 randomized controlled trials that compared one or more probiotics with placebo in adults with IBS; one trial was of probiotics plus acupuncture versus acupuncture only. Treatment had to be at least 1 week in duration for study inclusion. The authors evaluated the quality of studies using the widely used Jadad scale. The studies were generally of good quality, with 11 of 18 having a score of 4 or 5 out of 5. Most studies used the Rome II criteria to define IBS. Ten studies with 918 patients reported the outcome as improved versus not improved, and the summary effect was in favor of treatment (number needed to treat = 4). However, better quality studies, while still showing a benefit to treatment, found less benefit than more poorly designed studies. Fifteen studies with 1351 patients reported the outcome as a continuous variable, and the summary measure of effect also favored treatment in this analysis. In both cases, for dichotomous and continuous outcome measures, there was significant heterogeneity between studies (although this heterogeneity was resolved by discarding one outlier in the continuous outcome studies). There was no difference between types of probiotics studied (lactobacillus, bifidobacterium, streptococcus, and combinations of more than one probiotic). Regarding individual symptoms, there were statistically significant effects in favor of treating pain and flatulence, a trend for bloating (P = .058) and no effect on urgency. Most studies did not report adverse events; those that did found no significant problems. The standardized mean difference for the studies reporting continuous outcomes is also consistent with a small to moderate effect.


Site Licenses

Site license

Site Licenses are available for schools, universities, hospitals, government agencies, and companies. For more information, contact us.