Clinicopathologically, Behçet's disease is characterized by neutrophil and platlet hyperfunction. Lesions are formed presumably because neutrophils infiltrating the affected tissue release active oxygen and lysosomal enzymes in large amounts. The mechanisms of neutrophil hyperfunction was obscure, but in recent years attention has focused on the effects of cytokines released by mononuclear cells. As more has been learned about the etiopathogenesis of Behçet's disease, novel anti-inflammatory drugs, immunosuppressants, anti-thrombotic agents, and anticoagulants have helped to achieve remarkable progress of treatment. Particularly notable is the effect on severe uveitis of cyclosporine, which is more effective than colchicine and conventional immunosuppressants. Low dose weekly methotrexate therapy might have a beneficial effect in the treatment of patients with neuro-Behçet's disease.