YM 294 was administered for chemotherapy-induced thrombocytopenia in patients with gynecologic cancer at a dose of 50 microg/kg in order to examine the efficacy and safety by a randomized trial, using the non-treatment observation group as a control. Increase in the nadir platelet counts as well as shortening of the days to return the platelet number to>100,000/ microl were significantly higher in the 50 microg/kg groups, in comparison with the non-treatment observation group. The major adverse drug reactions observed in the 50 microg/kg groups were edema, erythema of injection site, and fever. All of these adverse reactions were either mild or moderate (not serious), and they resolved. Abnormal changes in laboratory value for which a casual relationship with the study drug could not be excluded were reversible and manageable. The efficacy and safety of 50 microg/kg groups for chemotherapy-induced thrombocytopenia in patients with gynecological cancer was confirmed by the results of this study.