Historical clue formulations

• Parliament constituent? — 2013-05-26
• Ingredient in some gum — 2009-08-13
• What some patches provide — 2008-05-24
• Source of addiction — 2006-11-03
• Stain maker — 2002-10-26
• Addictive stuff — 2000-03-01
• Certain craving — 1998-07-17
• Smokers' fix — 1995-05-03