Children chewing their nails may be caused by physiological reasons such as hunger, or it may be caused by a zinc or iron deficiency that leads to omnivorous fetishes or the child’s mental tension. The baby nibble nails, most of them may be hungry, through nail chewing, to express their own hunger, or for their own body awareness, is in the oral period of the baby, also like to eat hands, nail chewing to know the world, generally do not need special treatment, reasonable feeding, through the oral period, can generally improve on their own. If it is an older child, usually like to chew nails, may be caused by mental tension, may also be due to zinc deficiency, iron deficiency and other trace elements deficiency, resulting in the emergence of omnivorous fetish, manifested as like to chew nails, some children even like to eat dirt, wall skin, etc., it is recommended to go to the local hospital pediatric clinic in a timely manner, improve the trace elements and other tests to clarify, if the zinc deficiency, iron deficiency, need timely zinc and iron supplementation treatment. Therefore, if a child has nail chewing, if it is short-term and occasional, the possibility of physiological causes is high; if the child chews nails frequently and the growth and development is poor, it is considered that it may be caused by pathological reasons, and requires timely medical attention for further treatment.