The problem of diarrhea in children of different ages remains one of the topical areas of modern medicine. The study of the characteristics of the microflora in diarrhea is associated with the development of therapeutic and preventive measures for this condition. The intestinal microflora performs important functions in the child's body, including the exchange of energy substrates and the formation of intestinal immunity. At the same time, the intestinal microflora changes during the first years of life. In addition to age-related changes, gut flora changes with nutritional status, birth path, antibiotic exposure, genetic factors, and episodes of diarrhea.