Background and Aims: Steroid dependence and early relapse are frequent after a prednisolone-induced remission in Crohn's disease. The aim of this trial was to test whether mesalamine started at the onset of steroid tapering increases the rate of weaning from prednisolone and reduces the relapse rate after prednisolone cessation. Methods: One hundred fifty patients with active Crohn's disease were administered oral prednisolone (1 mg · kg-1 · day- 1) x 3-7 weeks; 129 patients went into clinical remission and were randomized to Pentasa (4 g · day-1) or placebo, administered until weaning and for 1 year thereafter. Results: Groups were similar for clinical and biological items collected initially. Weaning failure rate was 30% and 12% in the placebo and mesalamine arms, respectively. At the end of the trial, 9 of 36 patients administered placebo and 14 of 48 administered mesalamine were in remission. Both groups had similar time to relapse curves in the postweaning year; after adjusting for risk factors (high Crohn's Disease Activity index, white blood cell count of > 9 x 109 1-1 at weaning, and use of a medical treatment in the month before inclusion), Pentasa was found to be superior to placebo. Conclusions: After a prednisolone-induced remission in Crohn's disease, mesalamine facilitates steroid withdrawal and, during the postweaning year, may reduce the relapse rate in certain patient subgroups.