Cefixime, a new third generation oral cephalosporin antibiotic, was evaluated for safety and efficacy in the treatment of 206 children with acute bacterial pharyngitis, cystitis or pneumonia. Each patient had a throat, urine or sputum culture before therapy and was treated with a 10- to 14-day course of cefixime, 8 mg/kg once daily. Bacterial pathogens were isolated in 167 of 206 (81.1%). Streptococcus pyogenes (73.7% of isolates) and Escherichia coli (9.6%) were the most common Gram-positive and Gram-negative organisms, respectively. All patients were evaluable for safety, and 109 (52.9%) with pharyngitis (96) or cystitis (13) were evaluable for efficacy. Clinical failure occurred in 2 of 109 (1.8%) patients, both with pharyngitis; bacteriologic failure occurred in 1 patient with pharyngitis and 1 with cystitis. Five patients with pneumonia caused by possible pathogens also improved while taking cefixime. Drug-related adverse side effects occurred in 50 of 206 patients (24.3%); these were generally mild and led to discontinuing the antibiotic in only 4 patients (1.9%). The most common were diarrhea or loose stools (33 of 206, or 16%). Results of this study suggest that cefixime given once daily to children is safe and effective in the treatment of streptococcal pharyngitis and bacterial cystitis.