The patients who accepted the quadruple eradication program of the helicobacter pylori but failed to eradicate helicobacter pylori will be assessed the most suitable re-eradication time of helicobacter pylori.

Helicobacter pylori (HP) infection is a common global infectious disease, which is an important cause of chronic gastritis, peptic ulcer and gastric cancer.

At present, due to the non-standard Helicobacter pylori eradication program in clinical work, poor patient compliance and other reasons, the phenomenon of HP eradication treatment failure is more and more common. However, there is still no conclusion on the most appropriate time for remedial treatment in patients with Hp eradication failure.

Inclusion Criteria:

• Patients, aged between 18 and 70 years old, with positive H. pylori infection that was eradicated by previous therapies but failed are included. The H. pylori infection is confirmed by the positive rapid urease test or 13C-breath test.

Exclusion Criteria:

• Patients with significant underlying disease including liver, cardiac, pulmonary, and renal diseases, neoplasia, coagulopathy and genetic diseases, history of gastric surgery, pregnancy, breast-feeding, active gastrointestinal bleeding, the use of PPI, NSAID or antibiotics during the 4 weeks prior to enrolment, and previous history of allergic reactions to any of the medications used in this protocol. Patients previously treated with H. pylori eradication regimens or those unwilling to participate in the study were also excluded.

The patients in Shandong province,aged between 18 and 70 years old, with positive H. pylori infection that was eradicated by previous therapies but failed are included.