A recombinant human erythropoietin (rHu-EPO), was administered intravenously to beagle dogs at doses of 100, 500 and 2, 500IU/kg/day for 30 days. There were no significant clinical signs such as body weight, food intake, physical and opthalmic examination, urine analysis, etc. Any toxic response was not observed except for enlarged spleen and extramedullary hematopoiesis. No observed adverse effect level (NOAEL) of rHu-EPO for 30 days was considered to be 100IU/kg/day in beagle dogs.