Gastro-duodenal ulcer is a very frequent disease in Senegal and Helicobacter pylori (HP) being an ubiquitarian germ infects people living in developing countries in an over-early way and this most frequently. We have realized a prospective study dealing with 105 adult patients sent to hospital principal's endoscopy center. We were searching for HPs into three different methods which are as follows: using ordinary slats, clo-test, histological process. The results have confirmed the existence of a very high rate of infection due to HP, with among adults living in developing countries: 82% of our study. Likewise 95.8% of our ulcerous and erosive injuries at the bulb and 93.8% ulcerous and erosive gastric attacks were associated to HP infection. Those gastric and bulbar lesions were known to have followed a mild but chronic gastritis.