This idiom refers to curing a hangover by drinking more alcohol, based on the folk belief that a small dose of the cause can remedy its effects. It is often used literally for drinking but can metaphorically describe addressing a problem with more of the same behavior. The phrase is used in social, health, or humorous contexts, carrying a wry or self-deprecating tone, reflecting cultural attitudes toward indulgence and questionable remedies. It underscores the human tendency to seek quick fixes, often with a nod to the irony of such solutions.

The phrase originates from a 16th-century English folk remedy, where a dog bite was supposedly treated by applying the dog’s hair to the wound, based on sympathetic magic. John Heywood’s 1546 *Proverbs* recorded: ‘Take the hair of the dog that bit you.’ The modern use for hangovers appeared by the 17th century, with Samuel Pepys’ 1661 diary noting a ‘hair of the dog’ for drinking. It gained traction in 19th-century Britain, as seen in Charles Dickens’ *Pickwick Papers* (1837), and spread to American English during the temperance era. The phrase’s quirky imagery and relevance to drinking culture ensured its enduring use, especially in pub and literary contexts.