We compared the ulcer healing effect and eradication of H. pylori by one-week triple therapy of bismuth, metronidazole, and tetracycline with two-week dual therapy of amoxicillin and omeprazole. One hundred twelve patients with confirmed H. pylori infection and duodenal ulcers were recruited in a prospective, randomized, single-blinded trial. Ulcer healing, eradication of H. pylori in the stomach six weeks after randomization and side effect reported by patients during the therapy. Duodenal ulcers were healed in 44 of 49 (89.8%, 95% CI, 81.3-98.3 %) patients receiving triple therapy and in 44 of 53 (83.0%, 95% CI, 72.9-93.1%) patients receiving dual therapy (P=0.32). H. pylori was successfully eradicated in 41 of 49 (83.6%, 95% CI 73.4-94%) patients and in 40 of 53 (75.5%, 95% CI 63.9-87.1%) patients in the triple therapy group and the dual therapy group respectively (P=0.31). Side effects experienced by patients who received triple therapy were significantly more frequent than those who received dual therapy (P=0.0076). In conclusion, a two-week course of omeprazole and amoxicillin achieves a comparable rate of H. pylori and ulcer healing with fewer side effect.