Ten allogeneic bone marrow transplant (BMT) recipients with hepatic venoocclusive disease (VOD) were treated with recombinant human tissue plasminogen activator (rt-PA). Two of them subsequently underwent orthotopic liver transplantation (OLT). One additional patient with VOD underwent OLT without prior rt-PA treatment. Treatment with rt-PA was started a median of 14 (1--35) days after BMT. The dose of rt-PA given to adults was 10-50 mg i.v. and that given to children was 3-10 mg i.v. Treatment was given for 2-4 days. In three patients, the dose was administered over a longer period or it was repeated. Four patients responded to rt-PA therapy and six did not. Eight patients suffered from hemorrhages, one intracranial and three gastrointestinal. Four patients required blood transfusions. Four had minor subcutaneous hemorrhages and/or epistaxis. One patient died of intracranial hemorrhage and five from hepatic and/or multiorgan failure. Two patients treated with rt-PA, 10 mg/day for 4 days, are alive; one is alive and well 3 months after BMT, the other has relapsed after 7 months. The three patients undergoing OLT died of chronic hepatic failure, cerebral edema, and pneumonia. Our experience suggests that rt-PA should not be administered in high doses and that the treatment should not be given over a longer period, because of the risk of severe hemorrhages.