The patients who accept the quadruple eradication program of the helicobacter pylori and success to eradicate helicobacter pylori will be followed-up to observe the situation of re-infection of helicobacter pylori.

The patients with helicobacter pylori accepted he quadruple eradication program of the helicobacter pylori.They will be followed-up from 1 year to 5 years to observe the situation of re-infection of helicobacter pylori.The rate of the re-infection will be described by frequency and percentage.

Inclusion Criteria:

• Patients, aged between 18 and 70 years old, with positive H. pylori infection that was not eradicated by previous therapies 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 previous positive H. pylori infection that suceessed to be eradicated by therapies are included.