The efficacy and tolerability of ciprofloxacin (500 mg twice daily) was compared with that of amoxycillin/clavulanic acid (500 mg three times daily) in 76 patients with acute exacerbations of chronic non-cholesteatomatous suppurative otitis media enrolled in this open randomized multicentre trial. A total of 40 ciprofloxacin-treated patients and 35 amoxycillin/clavulanic acid-treated patients were evaluable for clinical efficacy following the 9-day treatment period. Pseudomonas aeruginosa was the main pathogen isolated prior to treatment. At the end of treatment, otorrhoea had disappeared in 57.5% of the ciprofloxacin group and 37.1% of the amoxycillin/clavulanic acid group (p = 0.04). Bacterial eradication rate was also significantly greater with ciprofloxacin (69.7%) than with amoxycillin/clavulanic acid (27.3%). Both treatments were well tolerated. Ciprofloxacin appears to be an effective treatment of chronic otitis media, and superior to amoxycillin/clavulanic acid.