The increase of antibiotic resistance to H. pylori causes failure of treatment. Furazolidone, amoxicillin and tetracycline are good candidates for rescue therapy since resistance to these three antimicrobials was rare. It is necessary to assess the efficacy and safety of these four bismuth-containing quadruple regimens with above antibiotics as empirical rescue therapies for H. pylori eradication.

Inclusion Criteria:

• H. pylori -positive patients with functional dyspepsia and scarred peptic ulcers who had previously failed one or more eradication regimens containing clarithromycin, metronidazole and/or amoxicillin.

Exclusion Criteria:

• less than 18 years old, never receiving eradication treatment before, with previous gastric surgery, pregnancy, lactation, major systemic diseases, administration of antibiotics, bismuth, antisecretory drugs in the preceding 8 weeks