Helicobacter pylori is a gram negative bacteria which has recently been associated to tissular changes of the upper digestive tract, however, the causal role has not yet been determined. Of 150 patients studied, 63 had tissular changes associated to Helicobacter pylori (Hp), 8 had Hp without tissular related changes (of whom 3 suffered bulbar ulcus and 1 gastric ulcus); the rest of the patients had hiatus hernia associated to distal esophagitis or pyloric stenosis; and only one patient was found to have normal tissue. A clear associated to distal esophagitis or pyloric stenosis; and only one patient was found to have normal tissue. A clear association between Hp and chronic or atrophic gastritis was determined, but no association was found between Hp and gastric cancer.