Three-year-old baby crying lips black, may be due to localized congestion, breath-holding syndrome or cardiovascular disease. 1. localized congestion: the baby will cause mental exuberance when crying, and at the same time, the mouth force, resulting in serious congestion of the lip area, which leads to black lips. 2. Breath-holding syndrome: Breath-holding syndrome is clinically common in young children under the age of three. The child may hyperventilate when crying, causing breath-holding episodes. When the symptoms attack will cause the baby to appear limbs straight, lips purple black situation. 3. cardiovascular disease: baby lips black, may be due to congenital heart disease, in the baby crying will lead to insufficient blood supply to the heart, thus causing the baby transient hypoxia situation, the appearance of lips black and purple. Three-year-old baby crying lips black, should be promptly to the hospital for examination, clear treatment plan, to avoid self-medication blindly.