To evaluate the safety and efficacy of glycosylated recombinant human granulocyte colony-stimulating factor (rhG-CSF) derived from Chinese hamster ovary cells in bone marrow transplantation (BMT), we performed a multi-center phase II clinical study. Sixty-two bone marrow transplanted patients (46 with allograft, 16 with autograft) were enrolled in this study, and rhG-CSF was administered intravenously 30 min daily at a dose of 2, 5, 10, or 20 micrograms/kg/day for 14 consecutive days from day 1 or day 5 after transplantation. Compared with historical control, blood neutrophil recovery in greater than or equal to 5 micrograms/kg/day group was clearly accelerated without delay in other blood cells. Consistent with the acceleration of neutrophil recovery, the number of days with body temperature (greater than or equal to 38 degrees C) decreased during from day 15 to day 28. No adverse effects were observed, and there was no evidence that rhG-CSF affected the incidence of graft-versus-host disease and relapse rates of myeloid leukemia. These results suggest that the posttransplant use of rhG-CSF may be an efficient strategy for reducing the risk of bacterial and/or fungal infection complications in BMT.