Intervention: 450 patients with H. pylori infection are randomly assigned to receive one of the following therapeutic schemes: group A (5RA5RCT): rabeprazole (20 mg bid) plus amoxicillin (1 g bid) for 5 days, followed by rabeprazole (20 mg bid) plus clarithromycin (500 mg bid) and tetracycline (1g bid) for a further 5 days; group B (5RA5RCM): rabeprazole (20 mg bid) plus amoxicillin (1 g bid) for 5 days, followed by rabeprazole (20 mg bid) plus clarithromycin (500 mg bid) and metronidazole (500mg bid) for a further 5 days; group C as control: rabeprazole (20 mg bid) plus amoxicillin (1 g bid) and clarithromycin (500 mg bid.) for 10 days.