The human stomach renews its lining every three to four days.
Why it is true
Gastric acids are strong enough to dissolve metal. To prevent the stomach from digesting itself, the cells of the gastric mucosa constantly regenerate, creating a new protective barrier every few days.
Source: Scientific American
Would you rather be asked first?
This is the reading side of the site, so the answer is in the sentence above — that is the whole point of it. Test yourself works the other way round: the question comes on its own, and the fact and the explanation only appear once you have answered.
Related facts
It takes your body roughly 12 to 24 hours to completely digest a meal.
The stomach renews its lining every 3 or 4 days.
The human stomach produces a new layer of mucus every two weeks so it does not digest itself.
The human stomach replaces its lining every three to four days.