The impact of Helicobacter pylori (H. pylori) eradication on the gastric mucosa (GM) was studied in patients with gastroduodenal ulcers. Clinical and morphological changes in the GM were assessed in 122 patients 3-7 years (mean 4.4 +/- 1.3 years) after eradication therapy and in 12 patients who had undergone H. pylori eradication. Successful H. pylori eradication in the gastric antral and body mucosa reduced inflammation, the degree of chronic inflammation, the number of lymphoid follicles, and the magnitude of gland atrophy. There were no statistically significant changes in intestinal metaplasia. The patients who had not received eradication therapy showed no significant GM changes as compared to the baseline values. In the unsuccessful eradication group, inflammation statistically significantly diminished in the gastric antrum and body with a reduction in the density of H. pylori contamination.