Glycerol (also called glycerine or glycerin) is a simple polyol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. It is widely used in the food industry as a sweetener and humectant and in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. The glycerol backbone is central to all lipids known as triglycerides.

Glycerol is used in medical and pharmaceutical and personal care preparations, mainly as a means of improving smoothness, providing lubrication and as a humectant. Glycerol is a precursor for synthesis of triacylglycerols and of phospholipids in the liver and adipose tissue. Glycerol is also used to produce nitroglycerin, which is an essential ingredient of various explosives such as dynamite, gelignite, and propellants like cordite.