The objectives of the survey are to describe the use of antibiotics in general practice, in order to identify inappropriate use and to estimate the exposure to different antibiotic categories in the population. The data refer to the overall drug prescriptions issued in general practice during 1991 in Rome. Four million of antibiotic prescriptions were issued, corresponding to 9% of the overall drug prescriptions and to 11% of the drug expenditure in Rome. When considering all anti-infective drugs (antibiotics plus antivirals and immunostimulating agents) the prescriptions and the expenditure increase up to 13% and 18% respectively. Three therapeutic categories (penicillins, cephalosporins and macrolides) represent more than 50% of the antibiotic prescriptions. Among the general population, 34% received at least one anti-infective drug and each patient received on average 2.7 prescriptions during the year. More than 20% of the prescriptions refers to antibiotic categories (such as aminoglycosides and chloramphenicols) which are not considered as a first choice in general practice. The analysis shows that a considerable proportion of antibiotic prescriptions refers to therapeutic categories with negative benefit/risk profile. More appropriate use of antibiotics might reduce both adverse events and drug expenditure.