We studied the clinical efficacy and safety of the antifibrinolytic drug tranexamic acid (TA) in patients undergoing chemotherapy for acute leukemia. 54 newley diagnosed AML patients were treated with 1g of TA every 6 hours until the platelet count rose to above 20 × 109/l. Platelet transfusions were given, irrespective of the count, only when oral, mucosal or significant skin bleeding manifestations were observed. During induction, the average number of days with thrombocytopenia below 20 × 109/l was 14.4 ±7.4 and 4.6 ±4.1 transfusions were given in each course. During consolidation, the average number of thrombocytopenic days was 8.4 ± 8.5 and only 1.7 ± 1.8 transfusions were administered. In 11.5% of the induction and 32.1% of the consolidation courses, no platelet support was required. TA was tolerated very well and no side effects or thromboembolic complications were observed. Only in 6 of the 78 induction courses did a major bleeding event occur and there were none in any of the 53 consolidation courses. Thus it seems that TA therapy allowed a significant reduction in the use of platelet transfusions without submitting the patients to greater bleeding risks.