Sixteen patients underwent local fibrinolytic therapy for thrombosis or embolism of the main trunk or intracranial branches of the internal carotid artery. There were eight cases of complete thrombosis of the internal carotid artery, five proximal stenoses of the internal carotid artery with extensive thrombus, one thrombus of the carotid siphon and two middle cerebral artery emboli. Indications for treatment included transient ischemic attacks in 11 cases, cerebral ischemia after carotid arteriography in two cases, and after surgery for atheromatous lesions of the carotid bifurcation in three cases. The fibrinolytic therapy was initiated during carotid surgery in three cases, where extended thrombosis of the internal carotid artery was discovered, which was inaccessible to a Fogarty catheter. The other 13 cases were treated during arteriography procedures. Lysis of the clot was always obtained. One patient died of hematoma of the frontal lobe. All other patients survived and showed neurologic improvement. The neurologic outcome was dependent on the duration and the degree of initial ischemia. Fibrinolytic therapy appears to be beneficial therapy for certain cases of cerebral ischemia.