Nail biting in children is usually associated with micronutrient deficiencies and psychological factors. You need to go to the hospital for relevant examinations to find out the lack of trace elements, and psychological counseling if the physical condition is not abnormal. Common causes and related recommendations are as follows: 1. Lack of trace elements: If the body is deficient in zinc, it is easy to develop xenophilia, which is usually accompanied by malnutrition, yellow hair color and other symptoms in addition to nail biting. If the above symptoms occur, you should go to the hospital to check the trace elements in your body, and if you are diagnosed with zinc deficiency, you can take oral zinc gluconate solution under the guidance of a doctor; 2. Psychological factors: Psychological factors are important factors that cause children to habitually bite their nails. The relationship with classmates, parents, teachers and other surrounding people is not good, resulting in tension, anxiety, stress or low self-esteem and other emotions can not be relieved, they will bite nails to relieve the discomfort. Parents should pay attention to their children’s nail biting habits, observe their children’s emotional changes and mental health, find the root cause of the nail biting habit and intervene in a timely manner, and take their children to a psychologist for guidance if necessary. Note parents should gently remove the child’s hand when they find the child biting their nails, not violent to stop, not to mention scold, so as not to cause greater psychological shadows to the child. In addition, you should help your child trim his or her nails on a daily basis to prevent dirt from accumulating in the nails and from being swallowed when biting them. At the same time in the daily diet should also pay attention to nutritional balance, not to let the child develop the habit of picky and partial food.