Acute respiratory infections (ARI), the leading class of ailments causing people to seek health care, rarely require antibiotics. Nevertheless, many physicians prescribe them needlessly. Hence, reducing the unnecessary use of antibiotics is one aim of any ARI control program. To help determine whether this aim might be achieved through a combination of refresher training for family physicians and public education campaigns, two 1991 interventions were carried out in four health areas (designated A, B, C, and D) in the city of Havana, Cuba. In each area, 10 clinics staffed by family physicians were selected through simple random sampling. In two areas (A and B), a refresher training program on ARI for health personnel was instituted at each clinic, while in areas A and C a community education program was set up. No intervention was carried out in area D. Simultaneously, from January through December 1991 trained individuals visited and administered a standard questionnaire every 15 days to 1,600 families (40 per clinic) systematically selected by random sampling. The aim of this procedure was to record the number of ARI episodes occurring among children under 5 years old, the treatment chosen in these cases, and whether antibiotics were employed. The results showed that when the two interventions were initiated, antibiotics were prescribed for 26%, 20%, 11%, and 19% of the mild ARI cases occurring in areas A, B, C, and D respectively (P > 0.05). In the period immediately following the interventions, antibiotic prescription rates declined by 26% and 63% in areas A and B, while increasing by 2% and 48% in areas C and D. Overall, prescription of antibiotics in the intervention areas A and B combined decreased by 54% (95% CI: 31-69%). These data suggest that a refresher training program for health personnel can rapidly reduce the unnecessary prescribing of antibiotics for ARI cases, but that public education alone does not appear effective.