A 8.5-month prospective study was performed in the Rhône area of France to study the incidence of infectious diseases in children in day care, and the qualitative and quantitative aspects of drug prescriptions for young children. The families of 1.359 children agreed to participate (98.5% of those selected). During the follow-up period 3.605 infections episodes were reported and 10.706 medications were used, an average of 3.0 medications per episode. Antibiotics were used in the treatment of 2.333 infectious episodes (65%) amoxycillin (36%), cephalosporin (23%), macrolide (17%) and trimethoprim-sulphamethoxazole (9%). Acetylsalicylic acid and paracetamol were used 865- and 1.568-times, respectively. Drugs with multi-active components represented 11.3% of the total number of systemic medicines reported. Paracetamol was prescribed in 59% of cases in a multi-active component drug, whereas this type of product accounted for 83.5% of the antihistamines (used 932-times). The rationale behind the paediatric prescribing habits of French medical doctors is discussed in relation to results previously obtained in other European countries.