The phrase “a little hair of the dog” describes an old remedy for imbibing too much alcohol, which consists of getting a taste of the drink that made you feel ill in the first place.
The origin of the phrase, however, comes from an even older remedy.
It was once believed that if someone was bitten by a dog, a hair from the attacking dog should be burned and then placed on the wound to prevent the victim from contracting rabies.
So drinking a little “hair of the dog” is the same, albeit equally ineffective, principle.
