Helicobacter pylori infection has been recognized as the most frequent causative factor of peptic ulcer disease. Pathogenesis has not been fully understood. However, peptic ulcer is always a consequence of dysbalance between aggressive and protective factors. Relationship of Helicobacter pylori and non-steroidal anti-inflammatory drugs remains a controversial issue. Therapy of peptic ulcer disease comprises besides anti-secretory therapy anti-Helicobacter eradication treatment. Successful eradication of Helicobacter pylori decreases significantly the relapse rate of peptic ulcer disease.