Chronic gastritis is not a “patent” for adults, but can also be seen in children, and the incidence of chronic gastritis in children has been increasing year by year, in which preschool children are not uncommon. The clinical manifestations of pediatric chronic gastritis are atypical and are often misdiagnosed as intestinal cramps, intestinal worms and dyspepsia, which delays diagnosis and treatment. The most common symptom of pediatric chronic gastritis is pain in the upper abdomen or around the umbilicus, and abdominal pain is mostly persistent vague pain or paroxysmal cramping pain, some of which may occur before or after meals, and some of which may also occur at night or without regularity. Children often cannot tell the exact location of the abdominal pain, and some of them indicate abdominal pain by crying. In addition, other symptoms include poor appetite, vomiting, fullness, weight loss, belching, anemia, and even gastrointestinal bleeding. Due to pain and reduced digestive function, children with yellowish color, weight loss, fatigue and so on. The clinical manifestations of pediatric chronic gastritis are often atypical, therefore, if parents find that their children have unexplained abdominal pain, at the same time, poor appetite, lethargy and epigastric pressure pain, they should think of the possibility of chronic gastritis, and take their children to the hospital for examination, and if necessary, gastroscopy to get a confirmed diagnosis. There are many causes of pediatric chronic gastritis, which are closely related to Helicobacter pylori infection, gastrointestinal dysfunction, and nutritional factors, among which Helicobacter pylori is the main causative factor of chronic gastritis. This bacterium is closely related to many gastrointestinal diseases, such as chronic gastritis, peptic ulcer and gastric cancer. The World Health Organization declared this bacterium as a carcinogen in 1994. H. pylori infects human beings and lives under the mucous membrane of the pylorus of the stomach, and can usually survive for decades. Most people have no symptoms after infection, and only some will develop related diseases. The mode of transmission is unknown and is thought to be either fecal-oral or oral-foam or human-to-human contact. The diagnosis of H. pylori can be broadly categorized into invasive and non-invasive methods. The invasive method involves taking gastric mucosal tissue through gastroscopy for bacterial culture, pathologic examination, and urease test. Non-invasive methods include blood sampling and urea breath test, fecal examination and urine examination. Among them, both breath test and fecal examination can achieve more than 95% correct diagnosis rate, while the reliability of urine examination has not been confirmed in children. Although non-invasive methods are more convenient than invasive methods, gastroscopy is still needed to diagnose chronic gastritis and ulcer. Warm tips: children’s gastritis and peptic ulcer are often overlooked by parents because of atypical symptoms, parents are asked to find children with the above symptoms, consult a doctor in time and do gastroscopy if necessary. Gastroscopy for children is similar to that for adults except that the diameter of the gastroscope tube is thinner and children may need anesthesia, which makes it a safe examination. Pediatric gastroscopy can be performed safely and accurately in well-equipped hospitals and by well-trained pediatric gastroenterologists.