The possibility that intra-arterial local infusion of fibrinolytic agents may achieve recanalization of previously occluded carotid territory arteries in acute stroke was tested in a prospective angiography-based open pilot study at two centers. Fifteen of 20 patients with acute symptoms (mean treatment-onset interval 7.6 hours) demonstrated complete recanalization; 10 of the 15 patients exhibited clinical improvement of varying degree by the time of hospital discharge. Four of the 20 patients suffered hemorrhagic transformation of the infarcted territory without clinical deterioration or demise. Because of the study format and the limited number of patients, dose responses for recanalization and risk relations were not established. We conclude that local intra-arterial fibrinolytic therapy may lead to cerebral arterial recanalization in acute carotid territory thrombotic stroke. The particular implications and limitations of this approach are discussed.