Weerts ZZRM, Masclee AAM, Witteman BJM, et al. - In patients with irritable bowel syndrome (IBS), researchers tested the safety and effectiveness of small intestinal-release peppermint oil and analyzed the impacts of targeted ileocolonic-release peppermint oil. From August 2016 through March 2018, they performed a double-blind trial of 190 patients with IBS (according to Rome IV criteria) at four hospitals in the Netherlands. One hundred eighty-nine patients were involved in the intent to treat analysis (mean age was 34.0 years) and 178 completed the study. Study participants were randomly assigned to groups given 182 mg small intestinal-release peppermint oil, 182 mg ileocolonic-release peppermint oil, or placebo for 8 weeks. In a randomized trial of IBS patients, the authors discovered that when using FDA/European Medicines Agency recommended endpoints, neither small-intestinal-release nor ileocolonic-release peppermint oil (8 weeks) yielded statistically significant decreases in abdominal pain response or overall symptom relief. However, the small intestinal-release peppermint oil reduced abdominal pain, discomfort and severity of IBS significantly. Though mild, adverse events were more common in both peppermint oil groups.