could you really filter saltwater via your rectum?

[CookingWithGas]

Nearly the same discussion in this thread starting with post #8. It includes the following:

@Qadgop_the_Mercotan

Sorry, a big NO!! for this one. And I am a doctor.

A seawater enema would pull water out of the body via the colon. And accelerate dehydration.

In fact, a standard recipe for salt water enemas is 1 tsp. of salt in 1 quart of fresh water. When given, it doesn’t overload the kidneys so much as a pure fresh water enema would, because much less water is absorbed due to that very small amount of salt! Double the concentration of salt in that recipe, and it will begin to pull fluids out of the body. A quart of seawater has close to 10 times that much salt in it!

@Sage_Rat

Unless the saltiness of the water caused the person to wretch.

It’s “retch.”