Clinical effects were investigated on cefadroxil powder for syrup (containing 100 mg of cefadroxil per 1 g) for acute bacterial infections (mostly scarlet fever) in the field of pediatrics, and the results were obtained as follows. Cefadroxil was applied in 100 cases of scarlet fever. Among 49 cases administered 30-39 mg/kg/day, the results were excellent in 34 cases and good in 15 cases, efficacy ratio being thus 100%. Among 38 cases administered 40-49 mg/kg/day, the results were excellent in 33 cases, and good in 5 cases, efficacy ratio being thus 100%. Out of 4 cases administered 20-29 mg/kg/day, the results were excellent in 3 cases and good in 1 case, while out of 9 cases administered 50-59 mg/kg/day, excellent in 4 cases and good in 5 cases. Among 78 cases of scarlet fever from which beta-hemolytic Streptococcus was proven from swab liquid of palatal tonsil, 67 cases received cefadroxil at a daily dose of 30-49 mg/kg, and the bacteria turned to negative the next day of administration in 72 cases, 2 days later in 6 cases. Cefadroxil was administered at a daily dose of 46 mg/kg for 7 days in 1 case of SSS syndrome of which Staphylococcus aureus was proven from skin lesion, and local bacteria turned to negative, as well as clinical effect was excellent. No pathogen was proven in 1 case of acute tonsillitis, maybe because ampicillin (ABPC) and cefazolin (CEZ) were administered before cefadroxil treatment, and yet a clinical efficacy was judged by administering cefadroxil at a daily dose of 46 mg/kg, though no clinical improvement was observed with the prior antibiotics. As to the side effects of cefadroxil in 102 cases, a slight vomiting was noticed in 6 cases, though the administration could be continued, and a slight rise of GOT or GPT was observed respectively in 3 cases and 1 case, all of which were recovered without abnormal clinical findings. Among the patients of scarlet fever, after beta-hemolytic Streptococcus became negative, reelimination or recurrence was noticed in 2 cases, but these patients were cured completely by readministration of cefadroxil or administration of amoxicillin (AMPC). Cefadroxil powder for syrup was absorbed quite well, its serum levels were maintained for long, and it was easily administered in children. Considering from its superior antibacterial activity, cefadroxil may be expected to be useful for a remedy in slight or middle infections of children.