Glycerin is a natural oil extracted from the seeds of the plant olive, and is the olive oil of the plant world. The Chinese name of glycerol is propanetriol, which is a colorless, sweet-tasting, clarified, viscous liquid, odorless with warm sweet smell, commonly known as glycerol, can absorb moisture from the air, also can absorb hydrogen sulfide, hydrogenated hydrogen and sulfur dioxide, insoluble in benzene, chloroform, carbon tetrachloride, carbon disulfide, petroleum ether and oil. Glycerin is used in medicine to make various preparations, solvents, hygroscopic agents, antifreeze and sweeteners, and to formulate topical ointments or suppositories. Glycerin is used in dermatology. Glycerin has moisturizing, hydrating, sunscreen and nourishing skin, and most of the cosmetics contain this ingredient. Patients with ichthyosis have dry skin due to atrophy of sebaceous glands and sweat glands, and frequent topical application of glycerin can have the effect of maintaining and caring for the skin. Glycerin is good for preventing dry lips and protecting the skin. Glycerin can be used as a lubricating laxative to gently treat constipation.