We report two patients with severe thrombocytopenia and life-threatening bleeding that were successfully managed with recombinant activated factor VII (rFVIIa). The ®rst was a 75-year-old male with Waldenstro È mÕs macroglobulinemia. During a therapeutic course with¯udarabine, he developed severe autoimmune thrombocytopenia resistant to conventional treatment, followed by persistent uncontrollable nasal bleeding. Platelet transfusions failed to increase the platelet count and control the hemorrhage. When hemoglobin levels fell below 8.5 g/dL and the patientÕs clinical condition got much worse, a single dose of 4.8 mg rFVIIa (90 lg/kg) was given as an i.v. bolus. Ten minutes after the rFVIIa injection, nasal bleeding stopped, the patientÕs clinical condition progressively improved, and splenectomy could be carried out uneventfully 2 days later. The second patient, a 52-year-old female, was under treatment for pre-B lymphoblastic leukemia. She developed severe thrombocytopenia, secondary to chemotherapy, complicated by massive gastrointestinal bleeding. Despite intensive treatment with platelet transfusions, hemorrhage continued and her condition deteriorated rapidly. She was then given an i.v. bolus injection of 4.8 mg rFVIIa, which resulted in cessation of hemorrhage and dramatic improvement of her clinical status. No adverse effects from the treatment with rFVIIa were observed. In conclusion, rFVIIa appears to be an attractive alternative for controlling hemorrhage in patients with severe thrombocytopenia, especially when platelet transfusions are unavailable or ineffective. Am.