In order to determine the efficacy of the antifibrinolytic agent tranexamic acid (TA) in reducing bleeding and platelet transfusions during the treatment of acute myeloid leukemia (AML), we conducted a randomized placebo-controlled double-blind study. Patients with AML undergoing induction or postremission consolidation chemotherapy were randomized into TA or placebo groups. Patients were not given platelet transfusions prophylactically but only when bleeding occurred. The severity of any bleeding event was scored. Thirty eight patients were randomized during induction. There were no significant differences between the two groups in the number of bleeding events and their severity or in the number of platelet transfusions given. Eighteen patients were studied during consolidation. In contrast, to the induction period, during consolidation there was a significantly less severe bleeding tendency in the TA group resulting in a lower platelet transfusion requirement [3.7 +/- 4.1 vs. 9.3 +/- 3.3 platelet units (p < .05)]. TA was well tolerated and no side effects were seen and no specific thromboembolic events were noticed. We conclude that giving TA during the thrombocytopenic period of AML patients undergoing consolidation chemotherapy is beneficial and safely reduces platelet transfusions.