To investigate the relationships between cisplatin and the related erythropoiesis impairment, 14 patients receiving very-high-dose cisplatin (40 mg/m2/day for 5 days) and 17 patients receiving standard-high-dose cisplatin (either a single dose of 100 or 20 mg/m2/day for 5 days) entered this study. Iron, ferritin, hemoglobin, and reticulocyte levels were evaluated before, 4 and 6 days after each course of cisplatin. A complete blood count was obtained weekly. During the 1st week after chemotherapy, iron and ferritin levels significantly increased, and the reticulocyte count decreased. Iron changes depend on the cisplatin dose, but are not related to the different schedules employed. The severity of subacute anemia was found to be dependent on the cisplatin dose administered and on hemoglobin pretreatment levels. Some relationships between cisplatin, iron changes, and the subacute hemoglobin decrease are described.