Thirty‐eight patients with particularly troublesome irritable bowel syndrome (IBS) were selected for trial on a 2‐week exclusion diet. Eighteen patients improved dramatically and, with two exceptions, subsequently identified foods to which they were intolerant. Follow‐up by postal questionnaire showed that at least 10 were still following their dietary restrictions 3–45 months later.Twelve of the 16 food intolerant patients were intolerant to more than one food. Fifteen patients found their symptoms did not improve on the exclusion diet. Five patients refused to try or were unable to complete the exclusion diet. The use of an appropriate exclusion diet for selected patients with IBS is reco