What's in a Name?
We’re often asked about the name of the shop. If we had any idea that half of the adult population had never heard of “Hair O’ The Dog”, we would have probably named the place “Clarence’s Cut-Rate Liquor Barn” or “Git Yer Booze Here” or something like that.
In any case, the phrase "Hair of the dog that bit you" refers to the practice of curing a hangover by drinking some of whatever it was that put you into that state in the first place. This usage has been around since 1546, when it appeared in Heywood's Proverbs:"What how fellow, thou knave, I pray thee let me and my fellow have a haire of the dog that bit us last night. And bitten were we bothe to the braine aright."
The origin of the phrase goes back even farther to the homeopathic practice of treating maladies with a bit of what caused the malady. In this case, one might treat a dog bite by rubbing hair from that dog upon the wound. Now we know why life amongst the ancients was solitary, poor, nasty, brutish, and short.