Xylitol is found in many plants and is usually extracted from birch trees. Chemically, it’s a type of alcohol that’s a carbohydrate (and it doesn’t actually contain alcohol). Xylitol is used as a natural zero-calorie sweetener and also in dental products.  Unlike other carbohydrates, xylitol doesn’t break down in the mouth (so it can’t cause cavities).  In fact, just the opposite occurs: “The bacteria that is responsible for cavities is called Streptococcus mutans and it can't utilize xylitol to grow. Over time, fewer and fewer of these bacteria survive on tooth surfaces, therefore, decreasing tooth decay,” says Dr. Ramezani.  So xylitol is a popular ingredient in natural toothpastes and other dental care products. However, some people may be sensitive to xylitol. The small amount of xylitol used in oral care products is usually well-tolerated says Dr. Ramezani. "But some people may experience bloating and diarrhea which are mild and go away shortly.” However, if this does happen to you, stop using the product.