This kind of emphasizes that to drink urine, it would have to be a last resort. Nothing ever good comes from a waste byproduct, even if most of it is water, it only takes a PPB (Part Per Billion) of a toxin to screw you up.



http://news.yahoo.com/s/ap/20070828/ap_on_re_as/china_miners_escape

BEIJING - The Meng brothers felt pretty good about their chances of making it out of the collapsed coal mine, until the sound of digging from outside stopped.
With no food or water, they were forced to eat coal and drink their own urine from discarded bottles.
Doctors have said the Mengs had kidney damage from lack of water but no other major injuries after being trapped for more than 130 hours.

Both coal and urine contain toxins, he said, and there is some debate about whether the benefits of recapturing some of the water in urine outweighs the risks of reabsorbing the toxins, which could lead to kidney damage or an altered mental state.