Gastric acid is the liquid secreted by the gastric glands of the stomach; its main digestive constituents are hydrochloric acid, mucin, renin and pepsinogen. The acid acts to aid in digesting food and killing unwanted bacteria and organisms that have been ingested with food.
Gastric acid is, together with several enzymes and the intrinsic factor, one of the main secretions of the stomach. Chemically it is an acid solution consisting mainly of hydrochloric acid, but also containing small quantities of potassium chloride (KCl) and sodium chloride (NaCl).