Zinc, as one of the essential trace elements, is involved in various metabolisms of the human body. Zinc deficiency can have the following clinical manifestations: a. Anorexia, when zinc deficiency decreases the function of taste buds, the sensitivity of taste is reduced, which results in loss of appetite and reduction of food intake. Zinc deficiency hinders the synthesis of nucleic acids and proteins, and leads to a decrease in food intake, which affects the growth and development of children. Delayed sexual development during puberty, such as small male genital testicles and penis, low testosterone content, low sexual function, late development of female breast and menstruation, late appearance of male and female pubic hair, etc. Overeating, children with zinc deficiency may like to eat mud, wall skin, paper, cinder or other foreign objects. Children with zinc deficiency may have reduced cellular and humoral immunity, which may lead to various infections, including recurrent colds, pneumonia and diarrhea. Skin and mucous membrane manifestations. In severe cases of zinc deficiency, dry skin, various rashes, herpetic dermatitis and recurrent oral ulcers may occur. Fetal growth and development may be delayed, with multiple malformations. Others, such as cataracts and reduced serum vitamin A due to vitamin A metabolism disorders, prolonged dark adaptation time and night blindness, etc.