Cefuroxime (CXM) was administered to 11 patients with pediatric bacterial infections, and clinical effective results were obtained in all these cases. Causative organisms detected in 5 cases with respiratory tract infection, and with urinary tract infections were all eliminated, and the bacterial count decreased in patients with colitis. As for side effect, 1 case developed eosinophilia, and another case with impaired liver function as underlying disease showed transitory exacerbated examination values. Time-course determinations of blood levels and urinary excretions were performed in 1 case. Fecal levels were determined in 2 cases but could not be detected; inactivation action of CXM was observed from the same fecal filtrate.