Modern medicine, both worldwide and nationally, has experienced in recent years important advances in the diagnosis of specific pathologies. One of the areas that has benefited most from these technological advances is gastroenterology and specifically upper and lower gastrointestinal endoscopy. The objective of this work was to establish the incidence of hypochlorhydria or achlorhydria and nitrites in the gastric mucosa in patients attended in the Gastroenterology Area of the Solca Riobamba Hospital as a trigger for Gastric Atrophy and Metaplasia, using as a method the upper digestive endoscopy, the analysis of gastric juice and later the biopsy obtained in this procedure. The sample consisted of 105 patients who underwent endoscopic examinations, where the importance of this examination and the usefulness of taking a biopsy in this type of lesions was determined. The relationship between the macroscopic findings and the histopathological result was also determined, as well as the most frequent type of inflammatory infiltrate diagnosed, as well as the pathologies found, all of the above characterized according to sex and age.