Recurrent retinal branch artery occlusions, carotid thromboembolism, cerebral venous thrombosis, transient brainstem ischemia, and massive brainstem and cerebral infarction complicated the course of inflammatory bowel disease in 5 patients. Three patients had ulcerative colitis and 2 had regional enteritis. The usual risk factors for stroke were absent. Neuropathological examination in 1 patient showed in situ thrombosis of small cerebral and brainstem arteries and veins. Coagulation studies showed thrombocytosis, short partial thromboplastin times, and elevation of fibrinogen and Factor VIII levels. Platelet counts and coagulation factors returned toward normal after control of intestinal inflammation in each of the 4 surviving patients. Inflammatory bowel disease can be accompanied by a hypercoagulable state that predisposes to stroke.