Laboratory and clinical studies on cefteram pivoxil(cefteram) a new cephem antibiotic, were carried out in the field of pediatrics. The results obtained are summarized as follows: 1. Serum concentrations, urinary concentrations and urinary recovery rates of cefteram (CFTM) were determined upon oral administration after meal of cefteram pivoxil (CFTM-PI) at doses of 3 mg/kg granules in 2 cases and 6 mg/kg granules in 2. Peak serum levels of CFTM were obtained at 3 hours in 2 cases and 4 hours in 2 cases after administration of the drug with a range of 0.74-2.2 micrograms/ml with half-lives of 0.77-3.62 hours. Urinary recovery rates in 8 hours after administration ranged from 9.6-23.0%. 2. MICs of CFTM against 22 clinical isolates (Streptococcus pyogenes 4 strains, Streptococcus pneumoniae 4, Staphylococcus aureus 2, Branhamella catarrhalis 1, Haemophilus influenzae 8, Haemophilus parainfluenzae 1, and Escherichia coli 2) were compared with those of cefaclor (CCL), cephalexin (CEX), and ampicillin (ABPC). The antibacterial activity of CFTM was superior to those of CCL and CEX, and was superior against Gram-negative rods and equal against Gram-positive cocci to those of ABPC. 3. Twenty-six pediatric patients with acute infectious diseases (scarlet fever 3 cases, tonsillitis 7, epiglottitis 1, bronchitis 5, pneumonia 5, urinary tract infection 3, cervical lymphadenitis 2) were treated with CFTM-PI at daily doses of 9.3-15.3 mg/kg t.i.d. as a rule. The efficacy rates were 100% clinically and 70% bacteriologically. 4. Side effects or abnormal laboratory test values were not observed except for an increased platelet count in 1 case.