Patients infected with H. pylori were randomly assigned to the dual therapy with vonoprazan 20 mg bid and amoxicillin 500 mg tid for 1 week or the triple therapy with vonoprazan 20 mg bid, amoxicillin 750 mg bid and clarithromycin 200 mg or metronidazole 250 mg bid bid for 1 week. Success or failure of eradication was determined by the 13C-urea breath test performed at 1 month after the therapy.

Patients infected with H. pylori were enrolled and invited to the study.

Patients who have never undergone the H. pylori eradication therapy are randomly assigned to the dual therapy with vonoprazan 20 mg bid and amoxicillin 500 mg tid for 1 week or the triple therapy with vonoprazan 20 mg bid, amoxicillin 750 mg bid and clarithromycin 200 mg bid for 1 week.

Patients who have ever failed in the eradication of H. pylori by the triple therapy containing clarithromycin are randomly assigned to the dual therapy with vonoprazan 20 mg bid and amoxicillin 500 mg tid for 1 week or the triple therapy with vonoprazan 20 mg bid, amoxicillin 750 mg bid and metronidazole 250 mg bid for 1 week.

Success or failure of eradication was determined by the 13C-urea breath test performed at 1 month after the therapy.

Inclusion Criteria:

• Patients infected with H. pylori
• Patients who are not allergic to any of drugs used in this study
• Patients who agree to participate to the study patients who are treatment naive for eradication of H. pylori

Exclusion Criteria:

• Patients not infected with H. pylori
• Patients who are allergic to any of drugs used in this study
• Patients who do not agree to participate to the study
• Severe general condition, such as renal insufficiency or liver dysfunction
• History of gastrectomy
• Inability to undergo eradication therapy
• Patients who have ever undergone the eradication therapy for H. pylori infection

The individual data cannot be taken out from the hospital without permission.