Urine is actually fairly bacteria free, unless you have a disease or something. It's made up primarily of urea (a posion) and any excess water. If the water content is high it will be fairly safe to drink if you don't leave it lying around for long.

Though the only time you'd want to drink it is if you're very dehydrated and in which case it's water content will be so low it is dangerous.

Orange juice anyone?