Saccharomyces Boulardii Combined With Bismuth Quadruple Therapy for Helicobacter Pylori Rescue Treatment

Inclusion Criteria: * Age between 18\~75, both gender. * Patients who had failed H.pylori eradication therapies . * Women are eligible if they are not pregnant or nursing, and if they are of childbearing potential they are required to use medically acceptable contraception for the duration of the study and 30 days thereafter. Exclusion Criteria: * Patients who have previously used tetracycline and furazolidone antibiotics to eradicate infection with H. pylori. * Contraindications to study drugs. * Substantial organ impairment, severe or unstable cardiopulmonary or endocrine disease. * Constant use of anti-ulcer drugs ( including taking proton-pump.inhibitors(PPI) within 2 weeks before the \[13C\] urea breath test), antibiotics or bismuth complexes (more than 3 times /1 month before screening). * Pregnant or lactating women. * Underwent upper gastrointestinal Surgery. * Dysphagia. * Evidence of bleeding or iron efficiency anemia. * A history of malignancy. * Drug or alcohol abuse history in the past 1 year. * Systemic use of corticosteroids, non steroidal anti-inflammatory drugs, anticoagulants, platelet aggregation inhibitors (except the use of aspirin for less than 100 mg/d). * Mental disorder. * Enrolled in other clinical trials in the past 3 months. * Refuse to sign informed consent.