When one hears of acid, a destructive and potent solution comes to mind. It seems like it has no business in the stomach of a living thing, except for aliens. Yet in the stomach of humans a quite powerful acid is secreted that is very crucial in the digestive processes, and without which, this process could not occur.

Yes in the stomach of a normal human gastric juices are secreted and are very instrumental in the digestion process. This gastric juice is composed of hydrochloric acid pepsin and rennet. Now these acids break down proteins. You see Meats and protein on whole are a rugged breed, and as such it takes some really drastic measures to break it down to make it ready for assimilation in your system. After this acid bath in the stomach proteins are then headed to the small intestine to be administered the second and last stage of digestion.

The acid is like the primary jaws on a stone crusher. It handles the big boys and breaks them down to size before sending them on the the secondary jaws to be completely dissolved. The reason why the acid doesn't dissolve your stomach walls is due to the lining that is present there covering the entire area, and is always replenishing itself, as some of it does get digested in the rush. It can be compared to a shark feeding frenzy, in the rush to eat lots of sharks inadvertently lose parts of their body to other sharks.