Clinical and bacteriological efficacy of topical ciprofloxacin hydrochloride was compared with that of intramuscular gentamicin sulfate in two groups composed of 30 patients each, all of whom were affected by chronic otitis media in the acute stage. Antibiotics were randomly given for 5 to 10 days according to the following schedules: ciprofloxacin hydrochloride, four drops (250 mg/mL in saline solution) administered locally twice a day, or gentamicin sulfate, 80 mg administered intramuscularly twice a day. We admitted to the study only adult patients affected by chronic otitis media in the acute stage with perforation of the tympanic membrane, without cholesteatoma, whose bacteriological culture was positive for Pseudomonas susceptible in vitro to ciprofloxacin and gentamicin. The clinical and bacteriological response was stated 12 hours after the interruption of the treatment, and 2 and 3 weeks later (follow-up). A favorable clinical result was observed in 26 (87%) of 30 patients under ciprofloxacin treatment; in 30 patients receiving gentamicin, a favorable clinical response was observed in 20 (66%) and bacteriological eradication in 13 (43%). No relapse at the follow-up was observed. Topical ciprofloxacin seems to be more effective than intramuscular gentamicin in curing Pseudomonas-caused chronic otitis media in the acute stage.