Since ancient times, trace elements have always existed in various animals, plants, minerals, medicines, food and drinking water, and played an important role in human health. With the development of science and technology, experts believe that trace elements are magical substances with special functions and the sixth indispensable nutrient element for human body. It is called the third generation medicine to check and treat diseases with the method of element balance dietotherapy. Trace elements are important carriers and electron transfer systems in the body. They are involved in the synthesis of hormones and vitamins and can affect the endocrine system. Many enzymes in the body need the participation and activation of trace elements, and it can also regulate the level of free radicals. A variety of elements * * * maintain normal nutritional status and physiological functions in the body. Facts have proved that the lack or excess of any element will make people sick and affect metabolism and growth and development. For example, zinc is one of the essential trace elements for all living things. If children are short of zinc, anorexia, lethargy, mental retardation, irritability, hyperactivity and attention deficit syndrome will occur. If the child is short of zinc, it will be anemia, anorexia and low immunity, which will directly affect the growth and development. When the elderly lack copper, they will be anemic, gray-haired and slow to respond. If they lack iodine, it will cause thyroid diseases and affect their intellectual development. In a word, the key to trace elements in human body lies in balance and integrity. Lack or excess will lead to health problems and even incurable diseases. For example, most patients with hypertension lack germanium, copper, cobalt and iron, but zinc, cadmium and lead increase in the body. Most senile cataract patients lack zinc, lithium, chromium, selenium, silicon and tin, but more are copper, magnesium and calcium.