Patients with irritable bowel syndrome were randomly assigned to three groups. The first group was given individualised Chinese herbal formulations, the second standard Chinese herbal formulations, the third a placebo. After 16 weeks all the patients were examined by both a traditional Chinese herbalist and an orthodox gastroenterologist.

The patients on Chinese herbs experienced significant improvement compared to those on the placebo but the patients given individualised treatment did no better than those on standard preparations. However, 14 weeks after treatment had been stopped the results had changed. Only the patients given individualised treatments maintained the improvement.