Boys lips purple is cold stimulation, peripheral circulation slowdown, cardiopulmonary diseases and other reasons related. 1. Cold stimulation: when the temperature drops, the local capillary contraction, causing purple lip color performance. 2. Slow peripheral circulation: anemia, angina pectoris, heart disease, resulting in poor blood circulation, slowing peripheral circulation, the phenomenon of purple lips. 3. Cardiopulmonary diseases: when there are diseases that cause respiratory failure, such as chronic obstructive pulmonary disease (COPD) or congenital heart disease (e.g., right-to-left shunt), can lead to cyanosis and the appearance of purple lips. Therefore, when there is a situation of purple lips, you can go to the hospital for oxygen saturation monitoring or do blood gas analysis test, to clarify the existence of hypoxia, so as to facilitate further treatment.