The clinical efficacy, safety and bacteriological eradication of Group A beta-haemolytic streptococci (GABHS) from the throat was studied after treatment of streptococcal tonsillopharyngitis with three commonly used oral antibiotics in a prospective, open labelled, comparative, randomised trial of 265 evaluable patients seen in one centre. All three antibiotics were administered in the recommended doses; penicillin V q8 hourly and clarithromycin q12 hourly were given for 10 days and cefprozil q12 hourly for 5 days. Clinical results and adverse events were similar for all three antibiotics used, with a prompt clinical outcome of >95%. Cefprozil had the best bacteriological eradication rate (failed to eradicate: 13.2, 15.1, 2.3; relapses: 13.2, 11.4, 5.7%, for penicillin, clarithromycin and cefprozil, respectively). Oral penicillin remains a clinically effective and safe antibiotic for the treatment of streptococcal pharyngitis. However, compliance and convenience for parents and children when they are asked to follow a 10 days course, especially when the patient has improved from the second or third day, together with the high incidence of bacteriological eradication failures, is an issue.