In a controlled study patients with Crohn's disease received an exclusion diet or an diet low in refined carbohydrates and rich in fiber. A total of 26 patients was observed for 1 year. The exclusion diet was not significantly superior to the standard diet with respect to the clinical course (Crohn's disease activity index according to Best or van Hees) or laboratory parameters of inflammatory activity. During dietary counselling relapses were infrequent and symptoms improved in both dietary groups.