I saw this on our local news tonight and learned a lot. I did a search here and didn't see anything posted about it so I thought I'd share.
Sugar Substitute May Be Dangerous to Dogs
SCHAUMBURG, Ill.
— If you think it's no big deal that your dog just ate some sugar-free gum or a cookie or two, think again. You may want to make an immediate trip to your veterinarian.
While veterinarians have suspected that the sugar substitute xylitol can make dogs sick, there is now further clinical evidence of an association between the product and possible liver failure in dogs. A clinical report appearing in the Oct. 1 Journal of the American Veterinary Medical Association (JAVMA) discusses the sometimes fatal conditions developed by dogs that have ingested xylitol. Xylitol, a sweetener found in many sugar-free chewing gums, candies, baked goods and toothpastes, is a naturally occurring ingredient that may have far-reaching negative health effects on dogs.
entire article can be read here
http://www.avma.org/press/releases/061001_xylitol.asp