My favourite source for all things connected to word and phrase origins is The Word Detective: Oh, He Falls Down Like That Every Year Dear Evan: Could you please tell me where/how the following two phrases originated? "Cold turkey," as in stopping a habit suddenly, and "On/off the wagon," as in drinking. -- Ken Shifman, via the Internet. Good evening, ladies and gentlemen, and welcome to Bad Habits Week in the wonderful world of words. For some curious reason, a high percentage of the questions I've been receiving lately have dealt with phrases associated with drunkenness or other "substance abuse" problems. Well, it is still early in the year -- perhaps everyone's New Year's resolutions just collapsed. I don't make New Year's resolutions myself. I just re-define all my bad habits as family traditions, which makes continuing to practice them seem downright virtuous. To "go cold turkey," meaning to stop using an addictive drug suddenly and completely, usually incurring extremely unpleasant symptoms of withdrawal, is a phrase which dates back to the beginning of the 20th century. "Cold turkey" is actually based on another colloquial phrase, "to talk turkey" (sometimes "to talk cold turkey"), meaning to face unpleasant truths squarely. It's not entirely clear how turkeys came to be associated with honesty and straightforward confrontation of difficulties, but it may simply be that turkey farmers were renowned at one time for their lack of pretense and blunt speech. The "wagon" in "on the wagon" (having sworn off drinking all alcohol) and "off the wagon" (having failed in one's resolve and thus having started drinking again) refers to a fixture of America's past, the water wagon. Before roads were routinely paved, municipalities would dispatch horse-drawn water wagons to spray the streets in order to prevent the clouds of dust that traffic would otherwise cause. Anyone who had sworn abstinence from alcohol (and would presumably be drinking largely water from then on) was said to have "climbed aboard the water wagon," later shortened to "on the wagon." http://www.word-detective.com/back-p.html#wagon

Quitting cold turkey generally refers to giving up a habit or behavior all at once. I'd guess that it might have something to do with how you'd serve a cold turkey, no preparation, just put it right out to be served, nothing gradual about the process.

Cold turkey 1: abrupt complete cessation of the use of an addictive drug; also : the symptoms experienced by a person undergoing withdrawal from a drug 2: unrelieved blunt language or procedure 3: a cold aloof person http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=cold+turkey 1. abrupt withdrawal of addictive drugs: a method of stopping drug addiction by not taking any further drugs and not having any other treatment to protect the addict from the withdrawal symptoms 2. withdrawal symptoms: the unpleasant symptoms, usually including nausea and shivering, that accompany a sudden withdrawal from an addictive drug 3. bluntly and undiplomatically: so as to convey the meaning to somebody in a way that cannot be misunderstood 4. drugs abruptly and completely: without a period of gradual withdrawal - "quit cold turkey" http://encarta.msn.com/encnet/features/dictionary/DictionaryResults.aspx?refid=1861687955 Meaning The state addicts are in when withdrawing from drug addiction. Also, predominantly in the U.S.A., plain speaking. Origin Of course, the term 'cold turkey' in the literal 'cold meat' sense appears many times in recipes - 'cold turkey salad' etc. Neither of the meanings above appear to have any allusory link back to that though. The most common use of the term is now in relation to drug withdrawal. The earliest reference I can find to that is from the Canadian newspaper The Daily Colonist, October 1921: "Perhaps the most pitiful figures who have appeared before Dr. Carleton Simon..are those who voluntarily surrender themselves. When they go before him, they [drug addicts] are given what is called the 'cold turkey' treatment." The 1936 edition of American Speech gave a definition of the term: "Cold turkey, treatment of addicts in institutions where they are taken off drugs suddenly without the 'tapering off' which the addict always desires." The 'plain talking/getting down to business' meaning of the term is largely limited to the U.S.A. The English newspaper The Daily Express explained that for an English audience in a January 1928 edition: "She talked cold turkey about sex. 'Cold turkey' means plain truth in America." There are many uses of the term in U.S. citations from the early 20th century. For example, this from The Oakland Tribune, August 1915: "This letter talks cold turkey. It gets down to brass." In the state of drug withdrawal the addict's blood is directed to the internal organs, leaving the skin white and with goose bumps. It has been suggested that this is what is alluded to by 'cold turkey'. That seems doubtful. It is much more likely that the allusion is to the direct, no nonsense approach indicated by the earlier 'plain speaking' meaning of the term. http://www.phrases.org.uk/meanings/96950.html