Use of cocaine in the USA, has reached epidemic proportions since 1983, when "crack" was introduced, its higher potency compared with cocaine HCl has been associated with a tremendous increase in the incidence of strokes. This study reports our experience with 55 cases of neurovascular events (25 ischemic and 30 hemorrhagic) related to cocaine use in 54 patients. Only 15 patients had other risk factors for stroke. Twenty six patients smoked "crack", 10 snorted cocaine and 12 injected it intravenously. Strokes occurred within 3 h of cocaine use in 15 patients with infarcts and 17 with hemorrhages. Ten infarcts occurred after an overnight binge. Of the hemorrhage group 9 were subarachnoid, 16 intracerebral (8 basal ganglia, 7 hemispheric and one brain stem) and 5 intraventricular. Computerized tomography (CT) showed an aneurysm of the anterior communicating artery, as well as one of the vein of Galen. Four aneurysms and 3 AVMs were identified on angiography. CT revealed 15 infarcts; it was normal in 7 patients with pure motor hemiparesis and in 3 with findings consistent with anterior spinal artery infarction. Several mechanisms may be responsible for the cerebrovascular complications. A sudden rise in systemic arterial pressure may cause hemorrhages, frequently in association with an underlying aneurysm or AVM. Vasospasm, arteritis, myocardial infarction with cardiac arrhythmias and increased platelet aggregation may provoke infarcts.