The main symptoms of acute gastritis – nausea, vomiting, abdominal pain, fever – occur in the initial period of many childhood diseases, including those requiring urgent medical measures (appendicitis, intussusception, peritonitis). This determines the exceptional complexity and responsibility of differential diagnosis. A significant difficulty is the differentiation with atypical forms of acute appendicitis. At the same time, clarification of the fact of food error preceding the development of acute gastritis, a large degree of intoxication in the initial period of the disease helps, on the other hand, the comparative intensity and increasing nature of abdominal pain with appendicitis. Invagination occurs mainly in young children, her clinic differs from the characteristic of acute gastritis in good condition and the absence of an increase in body temperature in the first hours after the appearance of mandatory vomiting with it, delayed stool and gas. The diagnosis of peritonitis is ruled out on the basis of the absence of symptoms of peritoneal irritation in acute gastritis. Differentiation with various infectious and somatic diseases (scarlet fever, meningitis, dysentery, pneumonia, etc.) is carried out taking into account the data of general and epidemiological history, clinical examination and observation.