Helicobacter pylori is one of the most common causes of chronic infections in human. A close relationship is now thought to exist between H. pylori and peptic ulcer disease, gastritis, and certain other gastroduodenal diseases. Also, it is now firmly established that infection with H. pylori is a key etiological factor in peptic ulcer disease, gastric mucosa-associated lymphoid tissue lymphoma, and gastric adenocarcinoma. Furthermore, several studies have shown that eradication of H. pylori plays an important role in the treatment of some gastric-intestinal diseases. Biopsy specimens were...