The reason why babies always bite the lower lip is that the desire to suck is not satisfied, to relieve the discomfort of teething and so on. 1. Sucking desire is not satisfied: the baby began to eat hands, nibble toys, nibble clothes, nibble all kinds of things he is interested in, if the parents immediately and compulsorily prevented these behaviors, the baby may be through the way of biting the lips to replace, secretly meet their psychological needs. 2. Relieve the discomfort of teething: baby teeth eruption, will stimulate the gum nerves appear painful and itchy feeling, in order to relieve this discomfort, the baby appeared to bite the lower lip. Remind parents, the baby often bite the lower lip, will affect the development of facial jawbone, and saliva often stimulate the skin will also occur saliva rash. Consultation is needed when necessary to avoid affecting the baby’s appearance and psychological development.