"Dude, I've gotta piss like a racehorse!"

Most of you probably recall those words from Fandango, often heard from the back seat of the car after having a few beers or a really large Coke. I often scratched my head wondering where the heck he came up with this and how it made any sense at all, but apparently it does according to this article from Slate:

The popular notion of incontinent racehorses seems to have roots in the late 1970s, when trainers began the widespread use of diuretics like Lasix (furosemide). Lasix inhibits the absorption of sodium and draws water into the bladder. This causes the horse to excrete more fluids, which could, in theory, make a horse lighter on its feet and faster on the track.