Mannitol

 Mannitol is a white, crystalline solid with the chemical formula C6H8(OH)6. It was originally isolated from the secretions of the flowering ash and called manna after its resemblance to the Biblical food. In plants, it is used to induce osmotic stress. It has several industrial uses, but is mainly used to produce tablets of medicine. Its fetal safety is "C" in Briggs' Reference Guide to Fetal and Neonatal Risk.Mannitol is classified as a sugar alcohol; that is, it is derived from a sugar (mannose) by reduction. Other sugar alcohols include xylitol and sorbitol. Mannitol and sorbitol are isomers, the only difference being the orientation of the hydroxyl group on carbon 2.