This randomized, multicentre prospective study was undertaken to compare the efficacy and tolerance of a one day course of injectable cefotaxime with a five day oral course of co-amoxyclav (amoxycillin plus clavulanic acid) in the treatment of acute otitis media in children. The study was conducted in 116 patients between the ages of three months and 12 years. No significant difference in efficacy was observed between the two treatment groups, but tolerance to the treatments differed significantly. There were no unwanted side-effects in the cefotaxime group whereas 22% of children in the amoxycillin plus clavulanic acid group suffered side-effects (P 0.0007). Short-course antibiotic therapy with cefotaxime appears to be a valuable alternative to conventional treatment regimens for acute otitis media in children.