He was bitten by a hairy dog.

Dear Matt:

Why does the "hair of the dog" theory work for hangovers, and where did the expression come from:

-- Dog-bit Don, El Paso, TX

Howdy, stranger. Physicians speculate that a hangover is just a mini-attack of alcohol withdrawal. In a bad bit of design engineering, our bodies can't metabolize alcohol as fast as we are determined to drink it. Our brains adjust to the gradually increasing alcohol level as we drink, but when we stagger home and hit the rack, the level drops and we suffer a sort of rebound effect. A slug of hooch kills the hangover but could give you to a new career as everybody's lovable, goofy town drunk. The expression comes from medieval belief that when a rabid dog bites you, if you chase him down, pull out some hair, and apply it to the bite, you won't get rabies yourself. Inflicting pain on the pooch may be the only satisfaction you get from that advice.