This prospective controlled randomized open-label clinical trial is designed to determine the optimal eradication rate of rabeprazole based sequential-concommitant hybrid therapies for adults infected with Helicobacter pylori in Eastern Taiwan. Enrolled patients will receive 3, 5 or 7 days of pre-concommitant (sequential part) treatment with rabeprazole + amoxicillin, then 7 days of concommitant treatment with rabeprazole + amoxicillin + clarithromycin + metronidazole.