Single intravenous and oral administration to SD rats and ICR mice of both sexes were performed to investigate the acute toxicity of DWC-751, a new parenteral cephalosporin. $LD_50$ values for ICR mice and SD rats administered intravenously with DWC-751 were as follows; 1151.1 mg/kg (male SD rat), 1183.5 mg/kg (female SD rat), 2698.1 mg/kg (male ICR mouse), 2833.0 mg/kg (female ICR mouse). It is suggested that $LD_50$ values in rats and mice of both sexes would be 5000 mg/kg in oral route. Major general symptoms induced by injection intravenously with DWC-751 are decreased motor activity, increased respiratory rate, tremor and convulsion. In oral route, piloerection and soft stool are observed to 4 day after administration. No significant body weight changes were observed at any level in the groups administered with DWC-751. The gross finding of rats administered intravenously was observed cecum distension.