Abstract
The lack of easily definable end points and the variable clinical presentation make it difficult to design appropriate therapeutic trials for the Irritable Bowel Syndrome. In this article, I have described the approach that our unit have taken. Aspects of trial design that are important include the selection of those who present with frequent (>3 times a week), and long standing symptoms (>6 months), the inclusion of a baseline as well as a placebo period so that placebo response can be assessed, a flexible dose regime, concomitant measurement of relevant physiological changes and assessment of the response of individual symptoms as well as global response so that the indications for a particular type of treatment can be determined.