Chronic gastritis (CG) refers to chronic inflammatory lesions of the gastric mucosa caused by various causes. Clinically, it mainly includes two categories, namely chronic superficial gastritis and atrophic gastritis. There are also some special types of gastritis, such as bile reflux gastritis, portal hypertensive gastropathy, uremic gastritis, etc. The main pathogenic factor of chronic superficial gastritis is Helicobacter pylori (H. pylori) infection. Repeated attacks of chronic gastritis can cause atrophy and intestinal metaplasia of gastric mucosal glands, and atypical hyperplasia of glands may occur in some cases. The pathogenesis is related to the long-term action of pathogenic factors that damage the mucosal barrier. The gastric mucosal barrier mainly refers to the defense and repair of the gastric mucosa, which can be divided into 5 levels. H. pylori infection can cause barrier damage at all links. It has been shown that chronic gastritis is very common in clinical practice, with the highest incidence rate among various gastric diseases, and is one of the diseases with the highest outpatient visit rate.