<P> To see a man about a dog or horse is an English idiom, usually used as a way to apologize for one's imminent departure or absence--generally to euphemistically conceal one's true purpose, such as going to use the toilet or going to buy a drink . </P> <P> The original, non-facetious meaning was probably to place or settle a bet on a racing dog . </P> <P> The earliest confirmed publication is the 1866 Dion Boucicault play Flying Scud in which a character knowingly breezes past a difficult situation saying, "Excuse me Mr. Quail, I can't stop; I've got to see a man about a dog ." In a listing for a 1939 revival on the NBC Radio program America's Lost Plays, Time magazine observed that the phrase was the play's "claim to fame". </P> <P> During Prohibition in the United States, the phrase was most commonly used in relation to the consumption or purchase of alcoholic beverages . </P>

Where does the expression going to see a man about a dog come from