Chronic gastritis refers to chronic inflammation or atrophic lesions of the gastric mucosa caused by different causes. Its essence is that after the gastric mucosal epithelium is repeatedly damaged, the mucosa undergoes reconstruction due to the mucosa's specific regeneration ability, and eventually leads to irreversible atrophy or even disappearance of the intrinsic gastric glands. This disease is very common, accounting for about 80-90% of patients undergoing gastroscopy. It is more common in men than in women, and the incidence rate gradually increases with age. Chronic superficial gastritis, atrophic gastritis, and chronic erosive gastritis are the two most common chronic gastritis. The clinical incidence of chronic gastritis in children and the elderly has also gradually increased in recent years.