Children always biting their clothes may be caused by anxiety and nervousness, the eruption of milk teeth and other physiological factors, and may also be caused by zinc deficiency, iron deficiency anemia and so on. 1. Physiological factors: If a child is anxious and tense for a long time, he may relieve his anxiety by biting his clothes. In addition, when children’s milk teeth erupt, the gums will appear uncomfortable feeling, at this time will relieve the discomfort by biting clothes. These are normal physiological phenomena and can be left untreated. 2. Zinc deficiency: Zinc deficiency may be caused by insufficient zinc intake and zinc absorption disorder. Patients may have symptoms such as xerostomia, anorexia, hair loss and skin lesions. If a child has a zinc deficiency, he or she may have the symptom of heterophagy, and the patient will always bite his or her clothes. 3. Iron deficiency anemia: Iron deficiency anemia is caused by increased iron demand, insufficient iron intake and excessive iron loss. In addition to xerophagia, patients will also have symptoms such as pallor, weakness, fatigue and xerostomia. Therefore, a child who develops xerophagia will show signs of biting clothes all the time. Children always bite clothes, there may also be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.