The goal of this trial is to determine the efficacy of levofloxacin based sequential treatment regimen or concomitant levofloxacin based regimens as empirical first-line therapy in the Syrian population

Inclusion Criteria:

• Patients are aged greater than 18 years old who have H. pylori infection diagnosed by any of following three methods:
• Positive rapid urease test (CLOtest).
• Histologic evidence of H. pylori by modified Giemsa staining.
• Positive 13C-urea breath test. without prior eradication therapy and are willing to receive therapy.

Exclusion Criteria:

• Children and teenagers aged less than 18 years.
• Previous eradication treatment for H. pylori.
• Patients who took any drug, which could influence the study results such as proton pump inhibitor, H2 blocker, mucosal protective agent and antibiotics.
• History of gastrectomy.
• Gastric malignancy, including adenocarcinoma and lymphoma,
• Previous allergic reaction to antibiotics (Amoxicillin, Tinadizole,
• Doxycycline,Bismuth subsalicylate,) and prompt pump inhibitors (Es- omeprazole).
• Contraindication to treatment drugs.
• Pregnant or lactating women.
• Severe concurrent disease.
• Liver cirrhosis.