HP and gastric outlet obstruction: Indeed while NSAIDs has been the major underlying factor in Hp-negative ulcers, several other hypotheses have also been suggested to explain the pathogenesis of Hp-negative DU including false negative results due to diagnostic methods, bleeding peptic ulcers, gastric outlet obstruction, perforated peptic ulcers, tobacco use, isolated Hp duodenal colonization, age, history of PUD, race, gastric hypersecretion, genetics, diseases of the duodenal mucosa, Helicobacter “heilmanii” infection and concomitant diseases [2].