dated slang Hard alcohol, especially whiskey. From the (false) folk remedy of drinking alcohol in order to slow one's metabolism after being bitten by a venomous snake, thus reducing the amount of venom that is able to circulate in one's body. My granddad always carried a little flask around with him, and whenever I asked him what he drank out of it, he'd wink and say, "Snakebite medicine." He was so full of snakebite medicine that you could practically smell him from across the room.