Why can't humans drink seawater?

Humans eat salt and drink water so why not seawater?

because if you drink seawater, jellyfish might grow inside of you, and then sting your intestinal tract.

http://www.newton.dep.anl.gov/askasci/bio99/bio99416.htm

Humans can't drink salt water because the kidneys can only make urine that

is less salty than salt water. Therefore, to get rid of all the excess salt taken in

by drinking salt water, you have to urinate more water than you drank, so you die of

dehydration.

You just can't. Why else would they invent objects to de-salt the sea water when you're stranded ona desserted island. I've never seen Swiss Family robinson but I think they did that. Not sure about Gilligan though

I think its fine if you drink some...but more than some and your in trouble(just as people who eat lots of salt). I'm thinking maybe 2 cups a day but this is only assuming you didn't have any sodium in your diet at all.

Wait, do you mean living on salt water as opposed to fresh water? You can drink salt water to do internal cleanses, but you don't live on it.

because salt is a protoplasmic poison. rub it on a fresh wound or in your eye and see