Because part of gastric cancer is developed on the basis of “atrophic gastritis and intestinalization”, many patients are highly nervous and review gastroscopy every year. In fact, only a few patients with “atrophic gastritis and intestinalization” involving the whole stomach need regular gastroscopy follow-up, while those with “atrophic gastritis and intestinalization”, which are very common and limited to the sinus of the stomach, do not need follow-up. ”Atrophic gastritis and enterocolitis” is a condition in which the glands of the normal gastric mucosa are destroyed and reduced (atrophy), leukocytes infiltrate (inflammation), and new cells in the form of intestinal epithelial cells appear (enterocolitis) due to various etiological factors. The main cause of “atrophic gastritis and intestinalization” is Helicobacter pylori (HP) infection. “Atrophic gastritis and enterocolitis are mostly confined to the sinus of the stomach, but can rarely spread to the entire stomach. There is no clear correlation between the clinical perception and the severity of the disease, i.e. people who feel that they have significant gastric disease may actually have mild atrophic gastritis and enterocolitis. After eradication of H. pylori infection, mild to moderate “atrophic gastritis and intestinalization” in the gastric sinus can be completely restored to normal (in severe cases, the whole stomach must be involved), while “atrophic gastritis and intestinalization” involving the whole stomach are not easily repaired, and very few of them can further develop into A very small number of them can further develop into gastric cancer. Therefore, eradication of H. pylori infection and regular gastroscopic monitoring of patients with atrophic gastritis and enterocolitis involving the whole stomach are the two main strategies for gastric cancer prevention and treatment. The methods used to confirm H. pylori infection include 13/14C-urea breath test, serum antibody test, rapid activator enzyme test, biopsy-grade pathology, etc. A reliable method to confirm the extent of “atrophic gastritis and enterocolitis” is whole gastric biopsy pathology, which means that during gastroscopy, in addition to the focal biopsy, at least one piece of tissue is taken from each of the four parts of the gastric sinus and the large and small curves of the gastric body for pathological examination. If all four sites show “atrophic gastritis and enterosis”, it indicates that the whole stomach is involved, but if it occurs only in the gastric sinus, it indicates that it is focal (note: the stomach is divided into two major parts: the sinus, which connects to the small intestine, and the body, which connects to the esophagus, using the gastric angle as the boundary). Measurement of serum pepsinogen I:II ratio can also help to detect “atrophic gastritis and intestinalization” involving the whole stomach. This can be used to screen for the need for gastroscopy and whole stomach biopsy. Pepsinogen I is secreted by the gastric mucosa, while pepsinogen II is secreted by both the gastric and duodenal mucosa. Under normal conditions, the secretion of I is much higher than that of II. In cases of atrophic gastritis and enterocolitis involving the whole stomach, the secretion of I is severely reduced while II is still secreted by the duodenum, so that the ratio of pepsinogen I:II decreases significantly.