Low-dose oral cyclosporine was used to maintain remission in patients with Crohn's disease. In seven patients, cyclosporine was used as a steroid-sparing agent; in 14 it was given for refractory active disease as an adjunct to conventional treatment, and then continued as maintenance treatment. Cyclosporine was given at an initial dose of 5 mg/kg reduced by 1 mg/kg at 2-month intervals until a maintenance dose of 2 mg/kg was reached. Of the seven patients in whom cyclosporine was used as a steroid-sparing agent, six had a relapse. Remission was achieved in seven of the refractory active group, but cyclosporine was withdrawn because of side effects in six of the patients in this group. Of the seven patients who had achieved remission, six subsequently had a relapse. Therefore, 12 of 14 patients (86%) in remission had a relapse despite cyclosporine maintenance. Ten of these (83%) had a relapse at a cyclosporine dose of 2 or 3 mg/kg. Cyclosporine levels at relapse (median, 74 ng/ml) were lower than the mean levels over the first 6 weeks of treatment (median, 130 ng/ml; p = 0.02). Our data do not support the use of cyclosporine to maintain remission in Crohn's disease.