One of the most toxic substances for dogs has only surfaced in recent years, thanks to the health-conscious minds of today’s consumers.  A particularly scary aspect of this ingredient is that it is not always listed on a food’s label, and can appear in unlikely sources.  Everything you need to know about xylitol and the dangers it poses to your dog is discussed here. What is Xylitol? Xylitol is a sugar alcohol that adds sweetness to food without the calories or insulin-spike of sugar.  It is commonly added to sugar-free or “diet friendly” foods in order to make these items more palatable.  In addition, xylitol is less likely to cause side effects in humans, such as gastrointestinal upset, which is commonly experienced with sweeteners such as sorbitol. Which Foods Contain Xylitol? The most common sources of xylitol are sugar-free gum, breath fresheners, toothpaste, and most recently, certain brands of peanut...