Children often bite their fingernails to consider the following aspects of the cause: First, consider whether the child usually developed a bad habit of life. This is often found in kindergartens or elementary school, where children often bite their fingernails, mostly in relation to parents not cutting their children’s nails in a timely manner. Second, also consider whether there are pathological factors, such as iron deficiency anemia in children will appear a kind of heterophagia, may appear to bite the nail situation, can be clarified through routine blood tests to determine whether there is a decrease in hemoglobin. Third, also consider whether the child bites the nail and the nail itself has a certain relationship. For example, if the nails are deformed during the growth process, or if the nails are malnourished, causing localized discomfort, the child may bite the fingernails, which can be examined by a professional dermatologist and then treated accordingly. Therefore, it is important to analyze from different angles and then give the appropriate treatment.