In a series of 10 patients with stereotactically treated basal ganglia haematoma rtPA was used to dissolve remaining clots. Pre-operative haematoma volume ranged between 39 and 111 cm3 (average 56 cm3). Stereotactic aspiration alone yielded an average volume reduction of 60% (range 23 to 78%). Haematoma cavity was instillated with rtPA repeatedly beginning 24 hours after the stereotactic intervention. At the end of rtPA therapy between 2 and 4 days after onset of the haemorrhage 67 to 92% (average 84%) of the initial haematoma was removed in all patients. More than 80% of the pre-operative clot could be removed in 8 out of 10 patients between day 2 and 4. There were no signs of rtPA related toxicity. At the end of the follow-up period (between 4 and 17 months--mean 8 months) 6 patients were awake, oriented and with a residual hemiparesis able to live in their familiar environment. It is concluded that local rtPA instillation is an effective additional treatment to further resolution of deep seated intracerebral haematomas after stereotactic aspiration.