Acute intravenous toxicities of rHu-EPO (recombinant human erythropoietin) were investigated in Sprague-Dawley rats. Seven days after administration of rHu-EPO, we examined the clinical signs, mortalities, body weight and etc. No clinical signs and mortalities of toxicity were observed in animals. Also, a significant change of body weights was not observed. These results suggest that LD$_{50}$ value was >25,000 unit/ kg in Sprague-Dawley rats and the acute intravenous toxicities of rHu-EPO were not significant.t.