Vitamins are a class of small organic compounds that maintain the normal function of the body, and vitamins are involved in the energy metabolism of the body. There are many kinds of vitamins, such as vitamin A, B, C, D and E. Vitamin C, also known as ascorbic acid, is a water-soluble vitamin. The functions of vitamin C are: 1. redox, which has the effect of scavenging free radicals in the body. 2. promoting wound healing, vitamin C is involved in a variety of important biosynthetic processes. 3. promoting the absorption and storage of iron. 4. promoting the absorption of calcium. 5. lowering cholesterol. It is mainly used clinically for the prevention of scurvy, but also for the adjuvant treatment of acute and chronic infectious diseases and purpura.