Peppermint (Mentha × piperita) is widely used to support or treat symptoms of Irritable Bowel Syndrome (IBS), and this use is supported by modern clinical evidence. The primary mechanism is attributed to the antispasmodic effects of peppermint oil, particularly its active component, menthol, which relaxes smooth muscle in the gastrointestinal tract by blocking calcium channels. Several randomized, placebo-controlled trials and meta-analyses have demonstrated that enteric-coated peppermint oil capsules can significantly reduce symptoms such as abdominal pain, bloating, and overall discomfort in IBS patients, compared to placebo. A 2019 meta-analysis in BMC Complementary Medicine and Therapies found that peppermint oil was superior to placebo in improving global IBS symptoms and abdominal pain, with a favorable safety profile.

The enteric coating is important, as it ensures delivery of the oil to the intestines rather than being released in the stomach, which can cause heartburn. Adverse effects are generally mild and infrequent. Guidelines from organizations such as the American College of Gastroenterology suggest peppermint oil as a therapeutic option for IBS, particularly for those with predominant pain and bloating. While peppermint has a long history of traditional use for digestive discomfort, the recommendation for IBS management is primarily based on clinical trial data in recent decades.