Background: Chronic gastritis is a slowly progressive disease. It includes atrophy of gastric mucosa, impairment of epithelial regeneration, formation of lymphoid tissue/germinal center, loss of gastric secretion and movement. The Mongolian traditional medicine used Anar-5 recipes for the treatment of stomachache, emesis, and improvement of gastricdigestion. Based on these observations, we implemented a rat model of Anar-5 treatment in artificial chronic gastritis in order to elucidate its potential protective mechanisms scientifically.Methods and material: We established an experimental rat model of chronic gastritis by use of ammonia water. We divided the rat cohorts in an Anar-5–treated test group, an untreated cohort, and a control group. The untreated group was fed with 0.1% ammonia water and the treated group with both 0.1% ammonia water and administered Anar-5 100 mg/kg/day for 6 weeks. Gastric lesions were evaluated microscopically. The Prostaglandin E2 levels, cyclooxygenase COX-2 expression and the cellular proliferation marker Ki67 were in addition assessed.Results: The Anar-5 cohort displayed with an increased thickness of the antrum mucosa, number (р˂0.05) and regeneration zones of gastric mucous epithelial cells when compared to the results of the untreated cohort (693.1±63.8 μm versus 429.6±43.5 μm). The untreated cohort displayed with decreased PGE2 levels (14.8±0.62 ng/dl) when compared to those of the control group and Anar-5 cohort (19.5±1.22 ng/dl and 8.7+0.32 g/dl protein, respectively). The Ki67-associated proliferation rate of the antrum mucosa was enhanced and measured 19.75% in the untreated cohort in comparison to a proliferation rate of 6.58% in the Anar-5 cohort.Conclusion: The data of our rat experiment indicate that a contemporary application of Anar-5 herbs acts as a gastric mucosal protective agent. In addition it induces an overexpression of COX-2 and maintenance of the PGE2 lev