Gastric acid is the hydrochloric acid which is secreted in the stomach. Digestion of food materials is the main function of gastric acid. This acid along with other digestive enzymes helps to degrade the food content into simpler forms. It also restricts the growth of microorganisms in the stomach. Despite the production of such corrosive acid, the stomach cells remain protected. This is due to the presence of a thick mucus layer in its wall which neutralises the acid effect and thus prevents cellular damage. In disease conditions, the effect of gastric acid causes the development of ulcers.