The total detectable rate of Helicobacter pylori (HP) of 485 patients suffering from gastric diseases was 59.6%. The HP in gastric mucosa of chronic atrophic gastritis (CAG) patients was separated from the cell culture in vitro and transferred successively. The mice were perfused with exciccate alum, and the rabbits with aspirin to injure their gastric mucosa, then HP was perfused. Result showed that the change of experimental animals was identical with that of CAG patients by means of bacteriological and pathological examination. It revealed that HP was in agreement with Robert Koch's three principles about pathogenic bacteria. According to the bacterial infectious hypothesis of CAG, 53 Chinese medicinal herbs and prescriptions were investigated with bacteriostatic test. Panax notogenseng and Magnolia officinalis were discovered to be sensitive, Prunus mume and Corydalis yanhusuo were moderate sensitive, and Coptis chinensis and Rheum palmatum highly sensitive to HP. Decoction of Clearing up the Heat and Relieving the Blood Stasis and No.2 recipe of Huowei were used to treat 70 CAG patients with Stomach Heat Syndrome. The effective rate of gastroscopic examination was 85.7%, that of pathological study was 80%. In comparing with the group of Shanjiu Weitai, there was significant difference between the traditional Chinese medicine treated group and Shanjiu Weitai control group, the former being markedly better.