The efficacy of bismuth-containing quadruple therapy with minocycline and metronidazole was not inferior to classical bismuth quadruple therapy for refractory H. pylori infection, though also accompanied with high occurrence of adverse events (55.4%). Optimization of minocycline-based regimen to achieve high eradication rate with fewer adverse events is imperative. This study aimed to compare the efficacy and tolerability of a 14-day bismuth-containing quadruple rescue therapy with different dosage of minocycline and metronidazole compared to classical bismuth quadruple therapy.

Inclusion Criteria:

• Ability and willingness to participate in the study and to sign and give informed consent
• Confirmed H. pylori infection and with previous treatment experience

Exclusion Criteria:

• subjects naive to H. pylori treatment,
• under 18 or over 80 years old
• history of gastrectomy
• pregnant or lactating women
• Previous history of tuberculosis
• Allergy to any of the study drugs
• severe systemic diseases or malignancy
• administration of antibiotics, bismuth, antisecretory drugs, or Chinese herb medicine in the preceding 8 weeks