A prospective, randomized study was performed in aplastic, granulocytopenic, infected patients with acute leukemia during induction therapy. 12 patients received antibiotics alone, and 13 received antibiotics plus 1.7-14.7 X 10(10) (MEAN 6.6 X 10(10) granulocytes by 1-5 (mean 2.7) daily transfusions. In 10 of 12 controls the infection resolved and remission was achieved with granulocyte counts greater than 500/mm3 15 +/- 9 days after randomization. In the transfused patients, infection was brought under control in 10 out of 13 and remission was achieved with granulocyte counts greater than 500/mm3 25+/- 11 days after randomization. Only one death due to infection was observed (6 days after randomization, control).