Xylitol is a sugar alcohol used as a sweetener. The name derives from , xyl[on], "wood" + suffix -itol, used to denote sugar alcohols. Xylitol is categorized as a polyalcohol or sugar alcohol (alditol). It has the formula CH₂OH(CHOH)₃CH₂OH and is an achiral isomer of pentane-1,2,3,4,5-pentol. Xylitol is roughly as sweet as sucrose (table sugar), with about 33 ewer calories per unit weight. Unlike other natural or synthetic sweeteners, xylitol is actively beneficial for dental health by reducing caries (cavities) to a third in regular use and helpful to remineralization. Multiple studies utilizing electron microscopy have indicated that xylitol is effective in inducing remineralization of deeper layers of demineralized enamel. Fair evidence was found that xylitol (as chewing gum, lozenges, nasal spray, etc.) reduced the incidence of acute middle ear infection in healthy children.