OBJECTIVE: To assess three prescribing strategies for sore throat. DESIGN: Randomised follow up study. SETTING: 11 general practices in the South and West region. SUBJECTS: 716 patients aged 4 years and over with sore throat and an abnormal physical sign in the throat; 84% had tonsillitis or pharyngitis. Patients were randomised to three groups: prescription for antibiotics for 10 days (group 1,246 patients); no prescription (group 2,230 patients); or prescription for antibiotics if symptoms were not starting to settle after three days (group 3; 238 patients). MAIN OUTCOME MEASURES: Duration of symptoms; satisfaction and compliance with and perceived efficacy of antibiotics; time off school or work. Outcomes were documented in 582 subjects (81%). RESULTS: Median duration of antibiotic use differed significantly in the three groups (10 v 0 v 0 days, P