The effects of weekly subcutaneous recombinant human erythropoietin (r-hEPO) administration on anemia during chemotherapy including cisplatin and 5-fluorouracil in patients with head and neck carcinomas were examined. Weekly subcutaneous r-hEPO administration in cancer patients has not been investigated previously. Patients were treated with r-hEPO 100 IU/kg (2 patients), 200 IU/kg (6 patients), or 400 IU/kg (5 patients), or placebo, and effectiveness was evaluated by monitoring hemoglobin concentration changes after administration for 8 weeks. Hemoglobin concentrations in all 3 r-hEPO dosage groups were higher than that in the control group during chemotherapy. All r-hEPO doses produced improvements in the anemia induced by chemotherapy; however, the 400 IU/kg dose was most effective. The requirement for blood transfusions decreased in patients receiving r-hEPO therapy, and no significant side-effects were associated with r-hEPO administration. These results suggest that chemotherapy-induced anemia can be prevented by weekly subcutaneous r-hEPO administration.