Xylitol is an all-natural sugar free sweetener that tastes and looks like sugar, but that is where the similarities end. Our bodies produce up to 15g of xylitol daily during normal metabolism. Xylitol is one of a group of sugar substitutes known as polyols. Others in the same group include sorbitol and maltitol, but they have 6 carbon structures and can be metabolised by harmful bacteria. However, xylitol has a unique 5 carbon structure metabolised only by friendly bacteria. Xylitol is a sweetener that occurs naturally. It can be found in berries and other fruits, some vegetables and in the woody fibres of birch tree and corncobs.