Purple lips in infants and toddlers usually refers to a child’s lips that are darker in color, appearing cyanotic and different from normal lip color. There are often multiple reasons for this condition. If an infant is born with purple lips, and if the color of the lips deepens when crying, or if there is also bruising at the end of the limbs, the child may have a congenital condition, such as congenital heart disease. Congenital tracheal stenosis and megalingualism can also prevent timely oxygen supply to infants and children, resulting in purple lips. Other conditions can also lead to the appearance of this phenomenon, for example, a baby who is frightened and often in a restless mood can also affect breathing and oxygen supply, leading to purple lips due to lack of oxygen. In addition, children with colds and nasal congestion that prevent them from breathing properly and freely can also have this problem. It is also common for newborns to have purple lips when their respiratory system is not yet perfect. If your baby does not have a cold and suddenly develops this symptom, be careful of acute lung lesions. There are many reasons for the baby’s purple lips, if the child has this symptom at birth, should be promptly checked for congenital heart disease and other diseases. If the baby is frightened or has a cold, it should also be treated and soothed in time.