Background and purpose: Eradication of Helicobacter pylori (H.pylori) is essential for the effective treatment of peptic ulcer (p.ulcer). Triple therapy as the first line of treatment in eradication of H.pylori is recommended. In this study, we aimed at comparing the efficacy of quadruple and triple therapies containing low dose furazolidone versus a triple therapy containing metronidazole and bismute.Materials and methods: In this study, 150 patients under endoscopy who had deodenal ulcer and confirmed for H.pylori were randomly enrolled with one of the following three methods of OAF omeprasol 20 mg BID, amoxycillin 1000 mg BID and furazolidone 100 mg BID or metronidazole 500 mg BID (OAM) and/or (OABF), omeprazol 20 mg BID, amoxycillin 1000 mg BID, furazolidone 100 mg BID and bismuth subcitrate 240 mg BID for 2 weeks. Eradication of H.pylori 12 weeks after treatment was assessed confirmed with 14-c urea breath test.Results: 150 patients, included 88 males and 62 females with mean age group of 40.3±11.5 were under study. In these three groups, there was no significant difference for ratio of male to female, mean age, smoking, gastrointestinal bleeding history, using of non steroid drugs, duration of observing symptoms and size of ulcer. Drug compliance for OAF, OAM and OABF were 94%, 96% and 98% respectively. Severe side effects (malaise, anorexia and diarrhea) of OAF were observed in 8%, in OAM 4% (headache and dry mouth), in OABF group 6% (malaise, nausea and dizziness). 140 patients could complete the treatment courses. Rate of eradication based on intention to treat for OABF, OAM and OAF were 72%, 40% and 54% respectively, and based on completion of the study were 73.4%, 40.8% and 57.4% respectively.Conclusion: Considering the obtained result, and in spite of priority of Furazolidone, none of the three mentioned triple theray regimens had required efficacy and are not recommended for eradication of H.pylori. In quaruple regimens containing low dose of furazolidone, eradication rate of H.pylori had significant increase, but was less than gold standard. Therefore in order to obtain ideal regimen, more study with low doses of furazolidone such as, moderate dose of furazolidone daily 300 mg in quadruple regimen for 2 weeks or even high dose of furazolidone 400 mg daily. In quadruple regimen furazolidone only in the first week and rest of drugs, are recommended. for 2 weeks.