Vitamin C is mainly used in oral and injectable formulations of vitamin C. Vitamin C is important for many vital activities of the body, it is involved in the formation of antibodies and collagen, and is important for the repair of tissues. It is also involved in the metabolism of amino acids and folic acid, and is important for the utilization of iron and carbohydrates, and for the synthesis of fats and proteins. In addition, vitamin C is very important for the maintenance of immune function and for maintaining the integrity of blood vessels. In clinical practice the drug vitamin C, for example, can be used to combat scurvy, which can develop in patients due to vitamin C deficiency. In addition, it can also be used in the adjuvant treatment of acute and chronic infectious diseases as well as purpura, for example, patients may use vitamin C when they suffer from some infectious diseases to play an adjuvant treatment role, while vitamin C can also be used in the adjuvant treatment of patients with cirrhosis of the liver. In conclusion, the main role of pharmaceutical vitamin C is to supplement vitamin C. For normal people it is not necessary to use pharmaceutical vitamin C. We are able to get enough vitamin C from food.