355 children, 3 months to 15 years old, presenting with acute otitis media, underwent a bacteriological study of otitis exsudate. From November 1985 to September 1987, 162 myringotomy and 149 acute otitis media spontaneously discharging were studied in Paris. From October 1981 to September 1987, 62 myringotomy and 46 spontaneously discharging acute otitis were studied in Valognes. There was none pathogenic bacterium in respectively 20 and 14% of the samples. Two or more pathogenic bacterium were isolated in 24 and 7% of the samples. In Paris as in Valognes, 3 pathogens were predominants: Haemophilus (17% were beta-lactamase producers), S. pneumoniae and Staphylococcus. There was only 5 and 3% Streptococcus pyogenes, 2% Branhamella catarrhalis in Paris, none in Valognes. Pseudomonas was present only in case of spontaneous otorrhea, even if recent. For the moment, the combination of amoxicillin with clavulanic acid is not our first treatment in case of acute otitis media in children. Actually we prescribe amoxicillin alone, 50 to 100 mg/kg/day. If the child is allergic to beta lactamin, we give him the combination of trimethoprime and sulfamethoxazole.