Background : Helicobacter pylori (H. pylori) infection is an important etiological factor in development of peptic ulcer. Eradication of H. pylori improves the cure rate of peptic ulcer and decreases the recurrence rate of these disease. However, the eradication success results have proven variable, and the factors influencing effectiveness of therapy are unclear. We performed this study to know treatment behavior for the eradication of H. pylori in peptic ulcer. Methods: We studied 214 patients retrospectively from medical records. All visited department of family medicine in one university hospital from August 1997 to May 2001 and were confirmed H. pylori infection by a positive Compylobacter like organism (CLO) test. Of 214 patients studied, 181 patients were treated omeprazole 20 mg bid, amoxicillin 1 g bid, clarithromycin 500 mg bid daily for 7-14 days. CLO test or histology or urea breath test were used to determine H. pylori eradication at 4 weeks later after eradication treatment. Results : Only 52 of 188 patients who took a eradication treatment were confirmed of the presence of eradication at 4 weeks later after treatment. The success rate of H. pylori eradication was 94.9%. Ulcer stage after therapy was improved. Conclusion : Our retrospective study showed that only 28.7% patients were confirmed of the presence of eradication, but overall eradication rate of confirmed patients was 94.9%.