There are very many reasons for the black and purple lips, the most common is the reduction of oxygen in the blood, it will produce the phenomenon of black and purple lips, the reasons for the reduction of oxygen in the blood: 1, serious lung infection, pulmonary insufficiency, chronic bronchitis patients, when the lung function decreases, the oxygen into the body is less, it will produce the phenomenon of black and purple lips; 2, when the heart disease, because of poor heart function, also lead to the body inside the blood Oxygenation is reduced, which also leads to hypoxia. Clinically, you may see patients with congenital heart disease, purple lips are suspected of heart problems; 3, temperature factors also have an impact, not all lips black purple phenomenon is a problem, in winter, you see many people’s lips will also be black purple, because the outside temperature is very low, resulting in blood circulation will be slower, the mouth local blood stay too long, oxygen consumption will lead to the phenomenon of blue lips, when in the temperature When the temperature is improved, this phenomenon of bruising will be relieved.