Cefamandole (sodium salt) was administered to total 32 cases of bacterial infectious diseases of children, and in 3 cases, there were investigated of these absorption and excretion. The results are as follows; 1. Blood levels: Cefamandole was given intravenous dose of 25 mg/kg to 3 children. The blood level of 15 minutes after intravenous injection was 140.4 micrograms/ml in average, and 0.3 micrograms/ml in average at 4 hours after intravenous injection. T 1/2 was 13.9 minutes. 2. Urinary concentration: Within 6 hours after intravenous injection, 51.8% of the drug was recovered in average from the urine and the urinary concentration reached to 3,050 micrograms/ml in average (0 approximately 2 hours), 1,262 micrograms/ml in average (2 approximately 4 hours), 41 micrograms/ml in average (4 approximately 6 hours) after injection. 3. RESULTS The drug was given 109 mg/kg/day (t.i.d. or q.i.d.) by intravenous route. The duration of administration was 11 days in average. The overall efficacy rate was 97%. In bacteriological results, excellent in 2, failure in 1, out of 3 strains. As side effects vascular pain was observed in 3 cases at the intravenous injection, and eosinophilia in 2 cases.