Peppermint oil mostly ineffective for IBS

Peppermint oil, regardless of whether it is released in the small intestine or in the ileocolon, is ineffective for overall symptom relief in irritable bowel syndrome (IBS), a new study has found. In contrast, it shows significant efficacy for abdominal pain, discomfort and disease severity.

Researchers randomly assigned 189 IBS patients to receive either 182-mg small-intestinal release (n=62; mean age, 32.0±11.0 years; 82.3 percent female) or 182-mg ileocolonic release (n=63; mean age, 34.4±13.1 years; 74.6 percent female) peppermint oil, or placebo (n=64; mean age, 35.5±15.2 years; 76.6 percent female).

The primary study outcome was abdominal pain response, which was defined as a drop in the weekly average of worst daily pain of at least 30 percent relative to baseline. This metric did not significantly differ in either the small-intestinal release (p=0.170) or ileocolonic release (p=0.385) peppermint oil group relative to placebo.

Similarly, global relief response was not significantly greater in either peppermint oil group relative to placebo (p=0.317 and p=0.351, respectively).

Exploratory secondary outcome analyses, however, found that small-intestinal release peppermint oil led to greater drops in 8-week daily worst abdominal pain vs placebo (p=0.016). This was also true for abdominal discomfort at weeks 6 (p=0.020), 7 (p=0.009) and 8 (p=0.025). There was also a significant positive effect on IBS symptom severity at week 8 (p=0.02).

Moreover, both peppermint groups reported significantly rarer use of rescue medication for pain. Ileocolonic release of peppermint oil had no significant effect on relief, reduction of abdominal discomfort, abdominal pain or IBS symptom severity.