Second Line Bismuth Containing Quadruple Therapy With Supplementary Probiotic

Exclusion criteria

• ✕. History of gastrectomy, surgery in the small intestine or colon
• ✕. History of gastric malignancy, including adenocarcinoma or lymphoma
• ✕. Allergic history, history of severe adverse effects or contraindication to antibiotics (Tetracycline, Metronidazole ), proton pump inhibitor, or probiotics
• ✕. Pregnant or lactating women
• ✕. Severe concurrent chronic or acute disease (e.g. renal failure, liver cirrhosis, or active malignancy)
• ✕. Concomitant use of clopidogrel or warfarin
• ✕. Recent (\<4 weeks) use of antibiotics, or recent (\<4 weeks) probiotic use duration \>2 weeks
• ✕. Not able to give consent on blinding or randomizatio