AIM:The eradication rate of Helicobacter pylori (H pylori)shows variation among countries and regimens of treatment.We aimed to study the eradication rates of different regimensin our region and some factors affecting the rate of eradication.METHODS:One hundred and sixty-four H pylori positivepatients (68 males,96 females;mean age:48±12 years)with duodenal or gastric ulcer without a smoking history wereincluded in the study.The patients were divided into threegroups according to the treatment regimens.Omeprazole20mg,clarithromycin 500mg,amoxicillin 1g were giventwice daily for 1 week (Group Ⅰ) and 2 weeks (Group Ⅱ).Patients in Group Ⅲ received bismuth subsitrate 300mg,tetracyline 500mg and metronidazole 500mg four timesdaily in addition to Omeprazole 20mg twice daily.Twobiopsies each before and after treatment were obtained fromantrum and corpus,and histopathologically evaluated.Eradication was assumed to be successful if no H pyloruswas detected from four biopsy specimens taken aftertreatment.The effects of factors like age,sex,H pylori densityon antrum and corpus before treatment,the total H pyloridensity,and the inflammation scores on the rate of H pylorieradication were evaluated.RESULTS:The overall eradication rate was 42%.The ratesin groups Ⅱ and Ⅲ were statistically higher than that ingroup Ⅰ (P<0.05).The rates of eradication were 24.5%,40.7% and 61.5% in groups Ⅰ,Ⅱ and Ⅲ,respectively.Theeradication rate was negatively related to either corpus H pyloridensity or total H pylori density (P<0.05).The median agewas older in the group in which the eradication failed incomparison to that with successful eradication (55 yr vs39 yr,P<0.001).No correlation between sex and H pylorieradication was found.CONCLUSION:Our rates of eradication were significantlylower when compared to those reported in literature.We believe that advanced age and high H pylori density arenegative predictive factors for the rate of H pylori eradication. AIM: The eradication rate of Helicobacter pylori (H pylori) shows variation among countries and regimens of treatment. We aimed to study the eradication rates of different regimens in our region and some factors affecting the rate of eradication. METHODS: One hundred and sixty-four H pylori positive patients (68 males, 96 females; mean age: 48 ± 12 years) with duodenal or gastric ulcer were not included in the study. The patients were divided into three groups according to the treatment regimens. Omeprazole 20 mg, clarithromycin 500 mg, amoxicillin 1g were giventwice daily for 1 week (Group I) and 2 weeks (Group II). Patients in Group III received bismuth subsitrate 300mg, tetracyline 500mg and metronidazole 500mg four times daily plus addition to Omeprazole 20mg twice daily.Twobiopsies before and after treatment were obtained fromantrum and corpus, and histopathologically evaluated. Eradication was assumed to be successful if no H pylorus was detected from four biopsy specimens. aftertreatment.The effects of factors like age, sex, H pylori densityon antrum and corpus before treatment, the total H pyloridensity, and the inflammation scores on the rate of H pylorieradication were evaluated.RESULTS: The overall eradication rate was 42%. rates rates groups Ⅱ and Ⅲ were higher than those of group Ⅰ (P <0.05). The rates of eradication were 24.5%, 40.7% and 61.5% in groups Ⅰ, Ⅱ and Ⅲ, respectively. The eradication rate was negatively related to either corpus H pyloridensity or total H pylori density (P <0.05). The median age was older in the group in which the eradication failed incomparison to that with successful eradication (55 yr vs 39 yr, P <0.001) .No correlation between sex and H pylorieradication was found. CONCLUSION: Our rates of eradication were significantlylower when compared to those reported in literature. We believe that advanced age and high H pylori density arenegative predictive factors for the rate of H pylori eradication.