BACKGROUND Opinions differ as to whether atrophic gastritis and intestinal metaplasia (IM) improve after Helicobacter pylori eradication. We investigated the change of the severity of atrophy and IM after H. pylori eradication. METHODS Twenty H. pylori-positive patients with histologically confirmed atrophic gastritis received anti-H. pylori therapy and achieved eradication. They were followed for 12-33 months (median 17 months) after the therapy. Biopsies were taken from the lesser and greater curvatures of the mid-antrum and middle body, and the incisura angularis of the stomach. The state of H. pylori infection was assessed histologically (Giemsa stain). Histological severity of atrophy and IM was graded according to the Updated Sydney System and scored on a 0-3 scale. The scores of atrophy and IM were compared between before and after the therapy (at the end of follow-up). RESULTS No significant difference was found in the scores of antral or body atrophy between before and after the therapy. Scores of antral IM increased after the therapy, whereas those of body IM did not change significantly. Development of IM in the whole stomach was found in three of seven patients who had no IM before the therapy. All of them were male smokers and drinkers. In contrast, complete regression of IM was not found. CONCLUSIONS Our results cast doubt on the reversibility of atrophy and IM after H. pylori eradication. Development of IM could be found in some of patients with atrophy even after H. pylori eradication.