"Our study investigated if herbal antidepressants such as St. John's wort could benefit irritable bowel disease patients," says Yuri Saito, M.D., M.P.H., gastroenterologist and lead physician scientist on the study. "Several of the chemical neurotransmitters that are in the brain are also in the colon. Therefore, it's been thought that antidepressants may affect sensation in the colon in a similar way to how they affect sensation in the brain. Our goal was to evaluate the usefulness of St John's wort in treating IBS."
In this placebo-controlled trial, 70 participants with IBS were randomized where half the patients received St. John's wort and the other half received a placebo for three months. In all, 86 percent of the participants were women, and the median age was 42 years. After three months of observing symptoms such as stomach pain, diarrhea, constipation and bloating, Mayo researchers found that the placebo group had a better response than the group taking the herbal supplement, St. John's wort.