Chronic gastritis is a disease accompanied by an indigestion in the stomach; morphological changes are reduced to non-specific inflammation of the gastric mucosa with the gradual development of atrophy. The anatomical and physiological features and close functional connections of the stomach with various body systems explain the frequent involvement in the pathological process in gastritis of other parts of the digestive system, as well as the nervous and endocrine. This equally determines the possibility of developing chronic gastritis in diseases of the intestines, liver, biliary tract, neuro-endocrine disorders, etc. The relationship between chronic gastritis and clinically similar functional secretory-motor disorders of the stomach, not accompanied by typical morphological changes in its mucous membrane, is one of the unresolved issues of gastroenterology. Given that the diagnosis of chronic gastritis in pediatrics is based primarily on the materials of clinical and functional observations, and the intravital histological study of the gastric mucosa in childhood is often significant difficulty, a strict distinction between the aforementioned functional disorders and chronic gastritis must be recognized as largely artificial ( M. B. Kossyura ). In each individual case, an attempt at such differentiation may be justified, but it should be remembered that the commonality of the etiology, clinic, and patterns of development allows us to talk about the pathogenetic unity of both pathological processes, one of which is, in fact, only a functional pre-stage of the possible development of chronic gastritis, with characteristic structural-morphological changes that have already arisen (O. L. Gordon). It is the difference in views on the essence of chronic gastritis and functional secretory-motor disorders of the stomach, as well as the lack of a unified classification and nomenclature that explains, first of all, the significant variety of information about the frequency of the disease in childhood. The most reliable are the data of A. V. Mazurin, obtained by endoscopy performed in 507 children with complaints of abdominal pain. Phenomena of chronic gastritis and gastroduodenitis (more often) were detected in 333 children (68.2%). The older the children, the more often they experience chronic gastritis. According to N. M. Smirnov, the ratio between the frequency of the disease in children of preschool, primary and high school age is approximately.