OBJECTIVE: To compare a topical quinolone antibiotic (ciprofloxacin) with a cheaper topical antiseptic (boric acid) for treating chronic suppurative otitis media in children. DESIGN: Randomized controlled trial. SETTING AND PARTICIPANTS: A total of 427 children with chronic suppurative otitis media enrolled from 141 schools following screening of 39 841 schoolchildren in Kenya. Intervention Topical ciprofloxacin (n = 216) or boric acid in alcohol (n = 211); child-to-child treatment twice daily for 2 weeks. MAIN OUTCOME MEASURES: Resolution of discharge (at 2 weeks for primary outcome), healing of the tympanic membrane, and change in hearing threshold from baseline, all at 2 and 4 weeks. RESULTS: At 2 weeks, discharge was resolved in 123 of 207 (59%) children given ciprofloxacin, and in 65 of 204 (32%) given boric acid (relative risk 1.86; 95% CI 1.48-2.35; P < 0.0001). This effect was also significant at 4 weeks, and ciprofloxacin was associated with better hearing at both visits. No difference with respect to tympanic membrane healing was detected. There were significantly fewer adverse events of ear pain, irritation, and bleeding on mopping with ciprofloxacin than boric acid. CONCLUSIONS: Ciprofloxacin performed better than boric acid and alcohol for treating chronic suppurative otitis media in children in Kenya.