Today, 6-year-old Xiaoming was brought to the Children’s Health Clinic by his mother. Upon seeing the doctor, Xiaoming’s mother said anxiously, “Doctor, my son has not cut his nails for more than two years, and every time he grows a little, he chews it off himself, and now sometimes he chews his toenails! What should I do?” The doctor took a look and saw that all the nails of Xiaoming’s ten fingers had been gnawed cleanly. Nail biting is a common bad behavior among children, foreign reports say that about half of all children at some time will appear this behavior, mostly seen in children aged 3 to 6 years. Most of this behavior goes away on its own as they get older, but a few may continue into adulthood, so we can also see that some adults still bite their nails. So what can cause nail biting? Generally speaking, there are two main causes: physiological and psychological. Physiological causes are mainly iron or zinc deficiencies that may cause omnivorous symptoms, in which case the child may eat non-food items such as nails, hair or mud. Psychological causes are more complex, as anxiety, depression, stress, and unfamiliar environments may cause nail biting, and some children may imitate the nail biting habits of others. Frequent nail biting can have a negative physiological and psychological impact on children. Children are naturally active and like to crawl around, and their nails carry a lot of bacteria, viruses and other pathogenic microorganisms, so when children bite their nails, they will undoubtedly bring a lot of germs and even parasites into their bodies; and in some environments where heavy metal pollution may exist, children who bite their nails are more likely to have excessive blood lead and other heavy metals. Children who bite their nails frequently can lead to thickening and shortening of fingertips, damage to nail beds, and even nail fungus; it can also lead to protruding upper jaw and misalignment of teeth in children; children who are accompanied by biting the skin of fingers can lead to thickening and swelling of local skin. Some children’s nail biting behavior is aggravated by negative emotions such as anxiety or depression, and if parents criticize or even scold them harshly at this time, they will aggravate their negative emotions, thus forming a vicious circle. Even if their children have nail biting behavior, parents should not be too anxious, we can try to correct nail biting behavior for children through the following methods: 1, parents do not care too much about nail biting behavior of children within 3 years old. For younger children, nail biting is a comforting behavior, and if parents pay too much attention to it and stop it, it may instead reinforce the behavior. 2, For some children who only occasionally bite their nails, parents should also take an attitude of ignoring them without much concern. Some children who suddenly appear to bite their nails frequently may be related to a stressful situation, and parents need to observe the circumstances under which the symptoms occur and help the child resolve the stress. 4. Some children who have been biting their nails since childhood may take longer to correct. For such children, parents should be more patient and not use scolding, ridicule, mockery, intimidation, etc. This will make the child’s emotions more tense and even produce unhealthy psychology such as low self-esteem. Parents should usually give more psychological attention to the child, encourage the child to make more friends, accompany the child to participate in parent-child activities or physical exercise, eliminate factors that cause tension and anxiety in the child, and gradually shift the child’s attention to nail biting in a positive way. 5, there are also some specific techniques to correct nail biting behavior, such as regular nail trimming for children, you can take pictures of the child’s own nail trimming before and after the comparison; small age children, you can paint some lemon juice, vinegar and other strange-smelling food on the nails, so that its nail biting while eating these foods, thus creating an aversion to nail biting, in order to achieve the corrective effect; in the fall and winter children can be made to wear gloves, which can also reduce the frequency of nail biting; and when children are biting their nails, they can be distracted with activities that require hand involvement (such as building blocks, painting, etc.) so that they can stop biting their nails.