Pharmacokinetic and clinical evaluation of cefpodoxime proxetil (CPDX-PR, CS-807) were performed in the field of pediatrics. The obtained results are summarized as follows. 1. Peak serum concentrations of CPDX upon single oral doses of 3.0 mg/kg and 4.4 mg/kg of CPDX-PR were 1.26-1.46 micrograms/ml and 1.45 micrograms/ml, respectively, achieved at 4 hours and 1 hour after administration. Urinary excretion rates for CPDX in the first 8 hours ranged between 28.1 and 30.2%. 2. Clinical efficacy rates for pediatric infections obtained at single dose levels ranging 3 to 6 mg/kg were 97.5%, and that at a single dose of 1 mg/kg were 90.9%. 3. Bacteriological effectiveness was determined in 45 strains identified in recent cases. Eradication rates for these bacteria at dose levels of 3 to 6 mg/kg and 1 mg/kg were 91.3% and 95.5%, respectively. 4. No side effect nor abnormal laboratory test data were found in any of the cases examined. From these results, CPDX-PR appeared to be a useful antibiotic agent in the field of pediatrics.