The patients who had shown the evidence of persistent H. pylori infection after the 1st eradication were enrolled for this study. After giving the informed consent about the method and efficacy (ITT and PP analysis) of the traditional 2nd rescue therapy and the tailored therapy for H. pylori infection based on culture and MIC, the patients were classified into the three regimen group under the patient's agreement and underwent 2nd eradication [14 days bismuth-based quadruple therapy (Proton pump inhibitor (PPI) regular dose b.i.d., tripotassium dicitrate bismuthate 300 mg q.i.d. (three tablets at 30 min before meals and one tablet at 2 hours after dinner), metronidazole 500 mg t.i.d., and tetracycline 500 mg q.i.d.), 14 days moxifloxacin-containing triple therapy (PPI regular dose b.i.d., moxifloxacin 400 mg q.d., and amoxicillin 1g b.i.d.), or tailored therapy based on H. pylori culture and MIC (select the 2nd rescue regimen between 14 days of bismuth-based quadruple therapy or 14 days moxifloxacin-containing triple therapy according to antibiotics susceptibility)].This study was analyzed the success of eradication for enrolled participants retrospectively, however the patients were enrolled prospectively based on previous study about antimicrobial susceptibility test for H. pylori in Korea.