Salt Water

[Neil14]

if the human body needs salt, how come when you drink saltwater it makes you sick?

[Whickerman]

I have blatantly ripped this answer off out of Wikipedia.

Accidentally consuming small quantities of seawater is not harmful. However some people cling to a persistent and incorrect belief that humans can survive at sea by drinking only seawater. This misconception probably originated from questionable reports claiming that the French physician Alain Bombard survived an ocean crossing using only seawater and other provisions harvested from the ocean.

The amount of sodium chloride in human blood and in urine is always kept within a very narrow range of 9 g per L (0.9% weight / volume). Drinking seawater (which contains about 3.5% ions of dissolved sodium chloride) temporarily increases the concentration of sodium chloride in the blood, so the only way to excrete the excess sodium chloride in the urine is by sacrificing internal water from cells. The cells eventually give so much water to try to dilute the salt that they die from dehydration, quickly followed by organs and eventually the organism.

Survival manuals consistently advise against drinking seawater. For example, the book "Medical Aspects of Harsh Environments" (Chapter 29 - Shipboard Medicine) [2] presents a summary of 163 life raft voyages. The risk of death was 39% for those who drank seawater, compared to only 3% for those who did not drink seawater.

[Doc Spock]

What Wickerman says.

[grasscarp]

Thats it then. I wont drink seawater.