Glycerol is a naturally occurring chemical. People use it as a medicine. Some uses and dosage forms have been approved by the U.S. Food and Drug Administration (FDA). It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. Glycerol is most commonly used for constipation, improving hydration and performance in athletes, and for certain skin conditions. It is also used for meningitis, stroke, obesity, ear infections, and other conditions, It is also widely used as a sweetener in the food industry and as a humectant in pharmaceutical formulations.