Two patients with angiographically proved basilar artery occlusion were treated with systemic recombinant tissue plasminogen activator (rtPA) according to protocol. The first patient was in a locked-in state and gradually deteriorated. On repeat angiography the basilar artery remained occluded. He died and necropsy revealed a pontine haemorrhagic infarction. The second patient, who was comatose and with decerebrate posturing, made a remarkable recovery. Angiography showed reperfusion. Therapy was initiated in the first patient after six hours and in the second after two hours. Treatment with rtPA is promising but probably not feasible for every patient. Success may depend on duration of occlusion and composition of occluding thrombus.