Up to 70% of Vietnamese people are infected with HP. This is the main cause of stomach and duodenal ulcers, which can lead to stomach cancer.

Helicobacter pylori (HP) is a gram-negative, flagellated spirochete found in and beneath the mucosal layer of the gastric epithelium. HP can survive in the acidic environment of the stomach. This bacterium secretes the enzyme urease, which helps neutralize stomach acid.