Background and aims: Among the infectious agents of acute intestinal infections in children such anaerobic microorganisms as C.perfringents, C.sordelli, C.difficile play a significant role. The studied on development of the methods for identification of Clostridii difficile. Aims: The purpose of our job was study the clinical-laboratory characteristic features of the acute intestinal infections in children of young age. Methods: We have studied 32 children at the age from 4 months to 3 years. In 86.2% of cases the children were hospitalized at the first week of disease that allowed to perform examinations at early time of disease. We used polymerase chain reaction (PCR) for identification toxin Clostridia difficile in diarrhea. Toxin Clostridia difficile was found from feces of the children with salmonellosis – in 30%, dysentery – in 10%, staphylococcus diarrhea – 20% and intestinal infections of unknown etiology – in 30% of cases. Results: Analysis of clinical data we revealed generalizations of infectious processes in 70% of patients as well as sepsis development. All patients had acute onset of the disease with higher temperature (70.1%), appearance of frequent stool to 10–20 times a day. Evaluation of the severity of diseases showed prevalence of the severe form (61.1%). Symptoms of intoxication were marked sharply. Hepatomegaly was noted in 46.2% and splenomegaly in 25.3% of children. In 15% of patients there was found myocardium damage (carditis). The hospital staying was 27.1 ± 2.1 days. Conclusions: The data obtained showed that diarrheal diseases produced by anaerobic microorganisms may be considered as serious problem which require special approach to the aspects of diagnosis and appropriate complex treatment.