The aim of this study is to determine the eradication rate in Helicobacter pylori (Hp) infection using omeprazole 20 mg twice daily, clarithromycin 500 mg twice daily and amoxicillin 1,000 mg twice daily for one or two weeks, in comparison with colloidal bismuth subcitrate 240 mg twice daily, amoxicillin 1,000 mg twice daily and metronidazole 400 mg twice daily for two weeks. 141 patients with Hp associated chronic gastritis or duodenal ulcer were randomly divided into 3 groups. Group I (n = 48) treated with triple therapy of omeprazole, clarithromycin and amoxicillin for 1 week. Group II (n = 47) treated with the same drug and dosage for 2 weeks. Group III (n = 46) treated with triple therapy of colloidal bismuth subcitrate, amoxicillin and metronidazole for 2 weeks. The Hp status was determined by rapid urease test and histology of Warthin-Starry silver stain. The eradication rates of Group I, Group II and Group III were 89.6%, 95.7% and 71.7% respectively. The difference between Group I and Group III, or Group II and Group III was significant. The difference of eradication rate between Group I and Group II was statistically insignificant. The frequency of side effects in Group III was higher than that in Group I or Group II. Although 21.1% of the patients in Group I and II experienced a metallic taste, none discontinued the medication. Our results show that triple therapy with omeprazole, clarithromycin and amoxicillin is an effective and well tolerated treatment for eradication of Hp infection and may be an alternative regimen to the old standard triple therapy.