We investigated the relationship between the eradication of Helicobacter pylori and the stage after the eradication of this bacterium. Eighty-six patients with H. pylori who had gastric ulcer (n = 45) or duodenal ulcer (n = 41) were enrolled in the study. As eradication therapy, patients received 1,500 mg amoxicillin, 400 mg clarithromycin, and 30 mg lansoprazole for 2 weeks, followed by 30 mg lansoprazole for 6 weeks in patients with gastric ulcer or for 4 weeks in those with duodenal ulcer. The ulcer stages were evaluated using the indigocarmine method at the third and sixth month after entry. The overall eradication rate of H. pylori was 85% in this study. In the gastric ulcer group, 62% of H. pylori-eradicated patients and 37.5% of H. pylori-uneradicated patients showed the S-2 stage (white scar) at the sixth month. In the duodenal ulcer group, 61% of H. pylori-eradicated patients showed the S-2 stage and none of the H. pylori-uneradicated patients showed the S-2 stage (p < 0.05). We concluded that H. pylori eradication might promote not ulcer healing but maturity of the ulcer scar, especially in duodenal ulcer patients, and that this might also be related to the reduction of ulcer relapse.