Puerperal infections are of great importance also under the conditions of modern obstetrics. There is a close connection with the problematic nature of hospitalism. The prospective study from 1,409 patients shows a puerperal fever at a percentage of 32.1%. Only 19.0% of the patients meet the criteria of a "standard puerperal morbidity". Within the complications occurring during the childbed period subinvolutio uteri holds the first place with 16.3%. The incidence of puerperal infections is influenced by predisposing factors dominated by the mode of accouchement. Ampicillin and chloramphenicol are the most used antibiotics. The preventive and therapeutic application of antibiotics is discussed. In the experimental part of the study the settlement of the vagina, the cervix, and the amniotic fluid is analysed. The evidence of causative organism for oxybiontic pathogenes partly also for anoxybiontic pathogenes and fungi is made. The fight against puerperal infections is particularly based on preventive measures. There must be mentioned a strict consideration of the antisepsis and asepsis as well as the restriction of predisposing factors. Under this precondition the wellaimed and indicated application of a therapy based on antibiotics will be successful.