The redness of the skin of the baby’s mouth may be caused by physiological factors, or it may be caused by disease factors. 1. If the baby is located in the environment temperature is high, or the baby body clothes wrapped too thick, will cause the baby’s skin, mouth skin capillary expansion, blood circulation accelerated, so as to show the phenomenon of the red skin of the mouth. 2. If the baby suffers from infectious diseases resulting in fever, it will also cause the baby to appear red skin, poor mental response, coughing, breathing faster and other manifestations. The baby’s mouth skin red, there may be other reasons, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.