Mannitol is a six-carbon polyol (sugar alcohol) that occurs naturally in plants, plant exudates and seaweeds; it is manufactured industrially by catalytic reduction of mannose, or by reduction and isomerisation of glucose followed by separation from sorbitol. With approximately 0.6 times the sweetness of sucrose and a characteristic cooling effect, its uses include nutritive sweeteners, anticaking agents (E421), stabilisers, thickeners and dusting powders for chewing gum, confectionery and pharmaceuticals. The name derives from manna, the sweet exudate of the ash tree (Fraxinus), from which it was first isolated — hence also called manna sugar. Like other polyols it is incompletely absorbed, so large intakes can have a laxative effect.