How is self-digestion of the stomach and small intestine prevented?

Question

How is self-digestion of the stomach and small intestine prevented?

Answer 1

He said it. Constant excretion of mucus.

Answer 2

The stomach and intestines secrete mucus, which coats the organs as a protective lining. Mucus is not affected by stomach acid or digestive enzymes, so the organs are safe.

If the mucus lining is damaged, the result will usually be ulcers, the main symptom of self-digestion.