Cefotiam (CTM) were clinically applied to 6 cases and the following results were obtained: 1. The patients were aged 1 year in 5 cases and 7 years in 1 case. They comprised three cases of acute tonsillitis and 1 case each of phlegmon, bronchopneumonia and cervical abscess. CTM was administered in a daily dose of 50-115 mg/kg t.i.d. by an 1-hour intravenous drip infusion for 4 to 8 days. 2. The causative bacteria were S. aureus in 3 cases and H. parainfluenzae, K. pneumoniae and unknown pathogen in each 1 case. The organisms were eradicated in all cases except for only 1 case of S. aureus. 3. Overall responses were good in 4 cases and fair in 2 cases. 4. As for the abnormal laboratory findings, slight increase of GOT and GPT was observed in 1 case. Any other side effects were not observed.