Objective To evaluate the effect of H. pylori eradication on the histologic changes in the gastric mucosa. Methods H. pylori-positive gastritis patients were divided into eradication group and control group. At the baseline and at the end of follow-up, all patients underwent endoscopy, biopsies for histological test. Result A total of 80 H. pylori-infected patients were divided randomily to eradication group ( n =40) and control group ( n =40). At 6 months, H. pylori eradicated in 29 patients was assigned to eradication group. In the control group, 27 patients remained H. pylori infected. Analysis of paired samples obtained from the same patients showed a significant decrease in acute and chronic gastritis ( P 0.05). In two groups, there were no significant changes in GA ( P =0.53 and 0.64).Conclusion H. pylori eradication can cure the acute and chronic inflammation and reduce, or even reverse the IM.