Did you know that some chewing gum is toxic to dogs? It is actually the sweetener in some chewing gum products that can be toxic. The toxic ingredient is called xylitol. Many pet owners have no idea about this, and I just read about it from Dr. Jon at petplace.com.
"Xylitol" is commonly found in sugar-free gum, candies and some baked goods. It seems some pets are more sensitive to it than others. The exact amount that needs to be ingested to cause problems is still being determined. Signs can develop quickly. So yes, something as simple as your dog eating a piece of your gum can mean a trip to the veterinarian.
So be aware of what your dog finds to chew on (pun intended!).