The chemical Xylitol is a sugar substitute that can be harmful to dogs. Varying amounts of the chemical are used in chewing gum. About eight to 10 sticks could be harmful to a 65-pound dog.
In addition to gum, Xylitol is used as a sweetener in sugar-free vitamins, pharmaceuticals and throat lozenges. Consumption of Xylitol can cause a dog's blood sugar to drop to dangerous levels and lead to weakness, lethargy, loss of coordination, collapse and seizures if the animal is not hospitalized. Pet owners should monitor what household items their dogs have access to in order to prevent the detrimental effects of Xylitol consumption.