1. During the first six months after the admission to day-care acute infections of children are very frequent. This gives rise to the question for the justification of the indication of antibacterial chemotherapy during this period. 2. During the mentioned period all acute illnesses and the corresponding therapies of total 361 children in Berlin, the capital of the GDR, Leipzig and Schwedt are analysed. 3. The local differences of the appearance of the antibacterial chemotherapy are not caused by the type and frequency of the diagnosis, but reflect the inadequate consideration for the therapy recommendations given by the Society of Pädiatrics. 4. The correlations between antibacterial chemotherapy and the appearance of acute respiration illnesses (ARI) suggest the influence of the bacteria on the origin of these illnesses of day-cared children.