O.J. Simpson wasted no time quenching his thirst for blood ... but he watered it down with vodka.
Simpson was spotted grabbing takeout Saturday at Las Vegas' Wahoos Fish Taco restaurant around 4 PM, where patrons tell us during the wait he ordered himself a Bloody Mary.
Everyone in the restaurant stared, but no one asked for pics or a John Hancock.
The restaurant wouldn't say what was in the bag ... customer/restaurant privilege.
He'd be wise to stay away from the blood stuff this time of year. Or always ... either way.