Peppermint oil capsules might relieve symptoms of irritable bowel syndrome

Reference

Ingrosso MR, Ianiro G, Nee J, et al. Systematic review and meta-analysis: efficacy of peppermint oil in irritable bowel syndrome. Aliment Pharmacol Ther 2022 Sep;56(6):932-941.

Synopsis

These investigators identified 10 randomized controlled trials (N = 1030 participants) by searching 3 databases, including the Cochrane Registry, as well as a clinical trial database, conference proceedings, and reference lists of identified studies. The studies all had a duration of at least 4 weeks and compared peppermint oil with placebo in adults with irritable bowel syndrome (IBS). Two investigators independently selected, abstracted, and evaluated the studies. Most of the studies had some risk of bias and there was significant heterogeneity among the study results. All but one of the studies used capsules that delayed the release of peppermint oil into the small intestine or lower in the intestinal tract. Comparing improvement in the combination of global symptom scores and abdominal pain, there was a greater percentage of participants who responded to peppermint oil than placebo (45.7% vs 27.7%; number needed to treat = 4; 95% CI 3 - 11). When evaluating just high-quality studies, there was still more benefit with peppermint oil than placebo, though not as much. Side effects — gastroesophageal reflux, dyspepsia, and flatulence being most common — were higher in the peppermint group (number needed to treat to harm = 7; 6 - 205). The single small study that evaluated peppermint oil drops found a small benefit on reducing abdominal pain.