A person produces enough saliva in a lifetime to fill two swimming pools.
Why it is true
Salivary glands produce about one to two litres of saliva per day, which, accumulated over an average lifetime, equals tens of thousands of litres of fluid.
Source: Dental Physiology
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
Human Body
You produce enough saliva in a lifetime to fill two swimming pools.
Human Body
A person produces between half a litre and one and a half litres of saliva per day.
Human Body
Humans produce enough saliva in their lifetime to fill two average-sized swimming pools.
Human Body
The human appendix is not a useless organ; it stores good bacteria.