Vitamins, as one of the essential nutritional elements for human health, generally cannot be synthesized in the body itself and are mainly obtained from the diet. Therapeutic vitamins are selected according to deficiencies and treated on an as-needed basis, such as vitamin A for the treatment of night blindness; vitamin B1 for foot disease; niacin for pellagra; vitamin C for scurvy; and vitamin D for rickets. Vitamins for nutritional supplementation are mainly used for people with dietary imbalance, and should be taken in small doses, in multiple varieties, frequently or continuously, so as to facilitate absorption and utilization; vitamins can be divided into two categories, fat-soluble and water-soluble, according to their physicochemical properties. The fat-soluble vitamins A, D and E are easy to accumulate in the body, and long-term overdose of vitamin A and vitamin D can cause poisoning; vitamin E has very low toxicity and is applied in regular doses without adverse reactions. Water-soluble vitamins, except vitamin K, are generally easy to excrete, not easy to accumulate, and non-toxic, such as vitamin B1, B2, C and other overdose, will soon be excreted out of the body; vitamin K is an anticoagulant drug, its dose must be strictly controlled. Vitamins can be understood as life-sustaining elements, a class of low-molecular organic compounds necessary for the health of the body, and are components of many coenzymes in the human body. Most of these substances cannot be synthesized by the body itself, or in small amounts, and must be obtained from food. The main role of vitamins is to regulate the metabolism of substances. If vitamins are lacking in food or cannot be obtained effectively from food, they may affect the body’s development, cause metabolic disorders, reduce the body’s ability to resist disease, and health conditions will be affected, and subhealth and even disease will occur.