The prescription pattern of empirical antibiotic treatment of community-acquired pneumonia (CAP) in seven European countries was studied based on data from published studies and prescription surveys. Overall, the three most commonly used compounds for outpatient treatment were aminopenicillins, aminopenicillins with clavulanic acid, macrolides and cephalosporins. The relative order of these three compounds varied very much between the different countries. Aminopenicillin was the first or second choice in four of seven countries. Cephalosporins were used mainly in Germany and in Southern Europe. In Italy parenteral treatment with third-generation cephalosporins or imipenem was the commonest choice (nearly 40%). Tetracyclines were used most in Northern and Central Europe. In contrast to the others, penicillin was the commonest choice in Sweden. Also for hospitalised patients the choice of initial antibiotic, as well as the use of mono- or combination therapy, varied significantly between countries. The varying treatment policies cannot be explained by scientific reason, such as differences in the aetiology of infection, frequency of penicillin-resistant pneumococci, pharmacokinetics, safety, nor by ecological or economic considerations. It is probable that local therapy traditions, and marketing factors, are equally important as the scientific rationale for the doctors' choice of empirical therapy for CAP.