Although available H. pylori eradication regimens in Japan fail to cure 10-20% of patients, an optimal re-treatment therapy for eradication-failure patients has still not been established. Since patient compliance, bacterial resistance and genotypic differences in CYP2C19 influence the eradication rate, re-eradication therapy should be selected, taking them into consideration. In the West, meta-analysis of the second-line treatment of H. pylori infection showed therapies comprising ranitidine bismuth and two antimicrobials are very effective re-treatment therapies irrespective of factors influencing H. pylori eradication. However ranitidine bismuth is not available in Japan and re-eradication therapy consisting of PPI, amoxicillin and metronidazole have been often undertaken and have achieved high eradication rate, even including patients with metronidazole resistant H. pylori.