The effects of helicobacter pylori infection on gastric disorders have been proven by many epidemiological and experimental studies. To explore the relationships between h. Pylori infection and gastric carcinogenesis, many factors, including host responses, environmental status, and the virulence factors of the bacteria should be taken into account. Mongolian gerbils ( meriones unguiculatus) can be easily infected with h. Pylori, and provide an excellent in-vivo experimental model to clarify the role of h. Pylori in active gastritis, peptic ulcers, intestinal metaplasia, and gastric carcinoma. Studies have revealed that h. Pylori infection markedly enhances all histological types of gastric cancers in gerbils treated with a chemical carcinogen. Eradication reduced the enhancing effect of h. Pylori on gastric carcinogenesis, whereas a high-salt diet synergistically enhanced the effect of h. Pylori. Various factors involving inflammation, cell proliferation, and cell differentiation could be examined with this experimental model to help elucidate this mechanisms of gastric carcinogenesis.