The relative rarity of stroke in oral contraceptive (OC) users, estimated at 14/100,000 women per year, does not mean that the risk is not significant; it is 4 to 9 times as high for OC users as for controls. 86 well-documented cases of stroke in OC users treated at a neurologic clinic in Paris between 1974 and 1984 are analyzed. There were 5 groups of patients: 1) 66 cases of cerebrovascular accidents, 64 of which were ischemic 2) 6 cases of intracranial venous thrombosis 3) 6 cases of benign and reversible intracranial hypertension or cerebral pseudotumor without demonstrated venous thrombosis 4) 5 cases of vascular complications in the retina or optic nerve, and 5) a miscellaneous group of 5 cases. The patients were aged from 16-49 years and the mean age was 30.5 years. The duration of use of OCs varied from a few days to 15 years, with an average of 39 months. 42 to 56% had family histories of cerebrovascular problems and 40 to 50% had personal or familial histories of migraine. Among 79 OC users with strokes, 41% used moderate dosed and 59% used microdose pills. No patients used microdose progestin only pills. There were 2 peak age groups of patients, those 25-29 and 38-42 years old. Young women aged 25-29 had intracranial venous thrombosis, intracranial hypertension or pseudotumor, and acute ischemia of the optic nerve. The average age of the 64 patients with ischemic cerebral vascular accidents was 31 years. Of the 30 infarcts, 1/3 left significant sequelae and 3 were fatal. There were 21 transitory ischemic accidents and 13 prolonged reversible ischemic accidents usually without sequelae. There were warning signals in 52% of infarct cases. 45% of patients with cerebrovascular accidents had family histories of cerebrovascular accidents or cardiac infarct and 40 to 50% had personal or family histories of migraine. Fewer than 25% had hyperlipidemia, 20% smoked, and 8% had diabetes or a problem of glycoregulation. Coagulation changes were found in 6 of 64 patients, but 22 of 26 had immune complexes and anti-ethinyl estradiol or antiprogesterone antibodies. Among the 6 cases of intracranial venous thrombolic accidents there were 2 deaths and 2 cases of very serious sequelae. The average age of these patients was about 27. The role of OCs is difficult to confirm because there are too few cases for statistical analysis. Antihormone antibodies were found in 3 such cases studied, but coagulation problems were not observed. Patients in the study who had laboratoratory or angiographic evidence of atheromatous disorders mostly were in the older peak age groups. The younger patients with cerebral ischemic accidents were largely without atheromatous lesions, but were very likely to have antiestrogen or antiprogesterone antibodies.