Among 21 patients with Behçet's disease, the results of various treatments were assessed. Treatment with chlorambucil, 0.1 mg/kg daily, compared favorably with corticosteroids. Uveitis and visual acuities improved in five of seven eyes when the patients were treated with chlorambucil, whereas improvement was observed in only four of 13 eyes when treatment consisted of corticosteroids. In 19 treatment courses among 14 patients with meningoencephalitis or recurrent meningitis, eight of nine patients treated with chlorambucil had remission of their disease; eight of 10 treatment courses with other agents--generally, corticosteroids--failed to induce remission in any of eight patients. Elevated cerebrospinal fluid cell counts returned to normal in five of nine patients treated with chlorambucil but remained elevated in five of six patients treated with corticosteroids. Two patients died, one who was taking prednisone plus cyclophosphamide and the other after prednisone plus multiple immunosuppressive treatments. Toxicity from chlorambucil included leukopenia (two patients), thrombocytopenia (one), bronchopneumonia (one), and amenorrhea (two). The duration of chlorambucil therapy averaged 1.8 years both for patients with uveitis and for those with meningoencephalitis.