Hydrochloric acid gastric secretion plays, among its primary physiological foundations, a role as protective barrier against infection with external agents from the diet and also contributes to the digestion of ingested food. However, this secretion is a critical factor shared by a number of highly prevalent diseases involving the upper gastrointestinal tract. Paradigms of such conditions include gastroduodenal peptic ulcer and gastroesophageal reflux disease.