The prevalence of H. pylori infection in China is 40-90%, with an average of 59%; the prevalence of presenting infection is 42-64%, with an average of 55%. The incidence of H. pylori increases with age, 38% for people aged 20-30 years and 78% for people aged 70 years, which is due to the increasing exposure to H. pylori with age. A, the transmission route oral-oral transmission, fecal-oral transmission; can be parasitic in the oral plaque. Second, precautions hand washing before and after meals; washing raw fruits and vegetables; in addition, low education, poor hygiene, crowded living conditions, children sleeping in the same bed with their parents can lead to the spread of bacteria. Third, the diseases caused by H. pylori 1, a variety of gastritis: gastritis, duodenal ulcer high toxicity type H. pylori, through the secretion of toxins and protein hydrolase, to damage the duodenal mucosa, and then cause inflammation, and even ulcers and perforation. 2, bad breath: H. pylori contains urease, which can transform urea into ammonia, bad breath is the smell of ammonia. Chronic gastric and duodenal ulcers: the toxins secreted by the highly toxic H. pylori from gastric ulcers can easily lead to gastric erosion and gastric ulcers. 3, gastric cancer: a large number of clinical cases show that the risk of gastric cancer in patients infected with highly toxic H. pylori is ten times or even dozens of times higher than that of uninfected.