Pee isn't sterile.

Pee has always been thought to be very sterile. New studies have found that it usually isn't, and can actually get infected. There is usually bacteria living in the bladder that makes your pee un-sterile. It was usually known that you can even drink your pee, don't do this. I don't see a situation where you would ever want to do this but, if you are ever stranded in a desert, do not drink your pee if you have nothing else to drink. Urine is full of salt, which can make you more dehydrated. Also, the bacteria in it will only make the situation worse.