Any alcoholic beverage, the consumption of which is supposed to clear up one's hangover from previous drinking (but will tend to have the opposite effect in reality). Origins of the phrase date back to medieval times, when hairs from a biting dog were put in the bite wound in the belief that this promoted healing.
Lloyd: What will you be drinking, sir?
Jack: Hair of the dog that bit me, Lloyd.
Lloyd: Bourbon on the rocks?
Jack: That'll do it.
Jack: Hair of the dog that bit me, Lloyd.
Lloyd: Bourbon on the rocks?
Jack: That'll do it.
by Carl Willis January 7, 2006
Get the hair of the dog that bit memug.