Edited from Wikipedia:

Urination is the primary method for excreting toxins, chemicals and drugs from the body. It is made up of a watery solution of metabolic wastes (such as urea), dissolved salts and organic materials. The fluid contains high concentrations of urea and other excess or potentially toxic substances.

Cellular metabolism results in a buildup of toxic nitrogen compounds, or nitrogenous waste. Since this waste is toxic, most animals have excretory systems (in humans this is known as the Urinary system) to rid themselves of this waste. The kidneys extract the nitrogenous wastes from the bloodstream, as well as excess water, sugars, and a variety of other chemicals.

Shipwrecked or people otherwise adrift at sea for long periods often resort to drinking their urine when no rainwater is available, seawater being unsuitable. People stranded in deserts often also drank urine to prevent life-threatening dehydration from setting in. However, this desperate measure achieves little to delay death from thirst as urine dehydrates one in the same manner saltwater does.


DON'T DRINK IT!

Sue