We aim to assess and compare the effectiveness of clarithromycin- and furazolidone-based regimens as primary therapies in eradicating H. pylori.

Helicobacter pylori plays a pivotal role in many diseases such as peptic ulcer disease and MALT lymphomas. And the prevalence of H. pylori is increasing in some parts of the world.

However, the eradication becomes increasingly difficult due to the growing antibiotic resistance. Bismuth-containing quadruple regimens are now recommended to serve as first-line therapies. Bismuth-clarithromycin-containing and bismuth-furazolidone-containing quadruple regimens are both in the list of the first regimens. And recent antimicrobial susceptibility tests showed us that the clarithromycin was increasingly resisted while furazolidone remained hardly resisted. The comparison between the effects of bismuth-clarithromycin-containing and bismuth-furazolidone-containing quadruple regimens is not so clear.

Inclusion Criteria:

• Patients, aged between 18 and 75years 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.