Two patients with acute embolic occlusion of the intracranial internal carotid artery and the lenticulostriate arteries were treated by local intraarterial fibrinolysis using tissue plasminogen activator. Although fibrinolysis started within 2.5 hours from the ictus, extravasation of the contrast medium from the lenticulostriate arteries occurred in the region of the basal ganglia. Local intraarterial fibrinolysis for acute embolic occlusion of the internal carotid artery may be a high-risk therapeutic intervention even within the ultra-acute stage, especially when the lenticulostriate arteries are occluded by an embolus.