Seventeen patients with Behçet's disease were treated with intermittent intravenous bolus injections of cyclophosphamide. Twelve patients had severe eye lesions, 7 had central neurological disorders and 2 had both ocular and central nervous system involvement. Cyclophosphamide was given during 4 weeks on average, in mean doses of 922 +/- 127 mg. Each patient received an average of 10 +/- 5 injections. The drug was generally well tolerated; only one patient developed moderate and transient hepatocytolysis. Visual acuity was improved in 12 of the 22 eyes with active lesions, and signs of inflammation disappeared in all cases. Neurological improvement was observed in 5 of the 7 patients affected, with complete regression of the disorders in 2 of them. In 16 patients who were also under corticosteroid therapy, steroid dosage could be significantly reduced by 44 +/- 11 mg per day.