Some traditional herbal medicines may - stress “may” - relieve the abdominal pain, bloating, diarrhea, and constipation that are the hallmarks of irritable bowel syndrome (IBS), according to a comprehensive review of published studies on the topic.

There is evidence that some Chinese, Tibetan and Indian herbal medicines “improve global symptoms of IBS,” investigators write in the report, published by The Cochrane Library. However, “it is premature to recommend herbal medicines for routine use in IBS,” Dr. Jianping Liu and colleagues conclude, because many of the published studies are small and most are of generally poor quality.

There is no cure for IBS, leading many sufferers to try herbal remedies to find relief. To gauge the effectiveness of herbal medicines for IBS, Liu and colleagues identified and systematically reviewed 75 published studies evaluating the effects of 71 different herbal preparations including single herbs or standard herb mixtures. These studies included more than 7,900 IBS patients.

Compared to treatment with an inactive placebo, several herbal medicines produced significant improvement in global IBS symptoms, the authors report. These include a standard Chinese herbal formula and individualized Chinese herbal medicines, STW 5 and STW 5-II; the Tibetan herbal medicine Padma Lax; the traditional Chinese formula Tongxie Yaofang; and the Indian Ayurvedic preparation of two herbs.

In six small trials, a combination herbal medicine and conventional medicine produced greater benefits than conventional therapies alone. Studies are needed to confirm this observation, Liu and colleagues caution.

While none of the trials reported serious side effects with the use of herbal medicines for IBS, more research is needed to determine the safety of herbal medicines in IBS patients, the authors warn.

“There is a great need for further rigorously conducted trials that look to see whether it is possible to replicate these positive effects,” said Liu, who works both at the Beijing University of Chinese Medicine and at the National Research Centre in Complementary and Alternative Medicine at the University of Tromso, Norway.

SOURCE: The Cochrane Library 2006.