Kawasaki syndrome is an acute, self-limited illness of young children which is characterized by prolonged fever, mucositis, skin changes, and cervical lymphadenopathy. Most investigators favor a microbial agent or agents as the trigger of KS followed by an immune-mediated vasculitis with a predilection for the coronary arteries. Serious complications include coronary artery aneurysms, aneurysmal thrombosis, and death. Aspirin has been the conventional treatment for KS, but it has not been shown to alter the basic pathology. Recently intact intravenous gamma globulin has been shown to reduce the frequency of coronary artery abnormalities. Definitive therapy of KS, however, awaits the discovery of its cause and pathogenesis.