Abstract: Helicobacter pylori(H.pylori)  is a microaerobic, spirally curved gramnegative bacillus, which is easy to be colonized in the stomach and is an important etiology of chronic gastritis. Cytotoxic factors such as cytotoxin  associated protein A, acuolating cytotoxin (VacA) and thioredoxin play an important role in the pathogenesis of H.pylori. In the early stage of inflammation, there may be significant accumulation of neutrophils in the mucosal lamina propria, and then the majority of patients will progress to chronic gastritis with lymphocyte infiltration. H.pylori infection can be manifested as diffuse redness, gastric nodule and gastric plica thickening under white light endoscopy. The absence of collecting vein, the enlargement of gastric fovea and the unclear display of subepithelial capillary network are the diagnostic indicators of H.pylori infection under image enhancement endoscopy. For H.pylori  positive patients with atrophic gastritis, it is strongly recommended to select  H.pylori treatment antibiotic regimen for eradication in the early stage to prevent the occurrence of gastric cancer.

Key words: gastritis, Helicobacter pylori, stomach neoplasms, endoscopy, digestive system