This study is a prospective and randomized double-blind clinical trial. The aim of this study is comparison of standard triple therapy with sequential therapy with base of levofloxacinand tinidazole in eradication of helicobacter pylori in patients with duodenal ulcer. Total of sample size is 168 patient with ages: 20-70 years old. The patients with a history of treatment of Helicobacter pylori, taking antibiotics, history of total gastrectomy, liver cirrhosis and uremia will be excluded. The patients are randomly divided into two groups with table of random numbers by computer. Assessor of results and patients do not know about the protocol of the study. First group, the first five days, receives pantoprazole, 40 mg twice daily, plus amoxicillin, 1 gm twice daily and the next five days receives pantoprazole, 40mg twice daily, levofloxacin 500 mg twice daily and tinidazole 500 mg twice daily. The second group as a control group receives omeprazole, 20 mg plus amoxicillin 1gr and clarithromycin 500 mg (All three drugs twice daily) for 10 days. Patients basic information such as age and sex, stature, Smoking, use of nonsteroidal antiinflammatory drug, alcohol intake, history of drug abuse will be recorded in both groups before treatment. Urea breath test results with c14 and endoscopy to check for Helicobacter pylori infection will be recorded in both groups before treatment and 8 week after completion of treatment period.