Xylitol and it's many names.  Please be aware because they are starting to add it to many different foods. 

Many dog owners are aware that chocolate, coffee, and grapes are toxic to dogs, but are unaware of the risk from ingesting the common natural sweetener, xylitol?  Xylitol is a natural sweetener that is found in a variety of products, including nut butters, chewing gum, toothpaste, mouthwash, nasal sprays, mints, floss, candy, chewable vitamins, and sugar-free baked goods. While xylitol offers many health benefits to humans, it can be deadly to dogs and should not be fed to any pets.

Ingesting 100 milligram of xylitol per kilogram of bodyweight may cause a rapid release of the hormone insulin, causing a sudden decrease in blood glucose (potentially life-threatening hypoglycemia, low blood sugar) for dogs. The drop in blood sugar occurs within 15 minutes, while the symptoms of hypoglycemia (vomiting, depression, loss of coordination, seizures, or coma are all possible symptoms) may be seen within 30 minutes after the dog consumes the xylitol-containing product. Exposure to higher doses of xylitol may possibly result in fatal liver failure in some dogs.