Cefuroxime (CXM), a new cephalosporin antibiotic, was used in pediatric field, and the following results were obtained. 1. Absorption and excretion CXM was administered by intravenous drip infusion to 3 patients aged 14 years, 1 year and 1 month, and 5 years and 3 months, respectively, at doses of 15.4 mg/kg, 14.1 mg/kg, and 13.2 mg/kg. The following blood levels were obtained; 71 micrograms/ml at the completion of infusion, 26.8 micrograms/ml at 30 minutes, 13.2 micrograms/ml at 1 hours, 5.05 micrograms/ml at 2 hours, 2.07 micrograms/ml at 4 hours, and less than 0.45 micrograms/ml at 6 hours after the infusion. Urinary excretion of the drug administered was measured in one of these cases. The urinary excretion rate at 1 approximately 6 hours after intravenous drip infusion was 50.4%. 2. Clinical result CXM 17 approximately 55 mg/kg were administered for 2 approximately 4 days to 6 patients with acute respiratory tract infection, 1 with acute cervical lymphadenitis, and 1 with acute enteritis. The clinical results was poor in the case with acute enteritis and good in the other 7 cases. No side effect was observed in 9 cases (the above 8 cases plus 1 unassessable case), and the laboratory examination results showed no abnormality, either.