The darkening of the face of patients with cerebral infarction may be related to environmental factors, or it may be caused by chronic obstructive pulmonary disease, renal insufficiency, cirrhosis of the liver and so on. 1. Environmental factors: If patients with cerebral infarction are exposed to ultraviolet rays for a long time without protective measures, darkening of the face may appear. 2. Chronic Obstructive Pulmonary Disease (COPD): If patients with cerebral infarction are combined with COPD, due to chronic ischemia and hypoxia, cyanosis of lips and black color may appear, which can be diagnosed by blood gas analysis, lung function test, lung CT and other tests. 3. Renal insufficiency: when patients with cerebral infarction are combined with renal insufficiency, they may have gray skin all over the body, which can be diagnosed by renal function test, renal ultrasound and other related examinations. 4. Cirrhosis: patients with cerebral infarction combined with cirrhosis will have symptoms such as loss of appetite, nausea, emaciation, recurrent bleeding from nose and gums, skin pigmentation, and darkening of face, etc., which can be diagnosed by liver function, abdominal CT and other related examinations. Cerebral infarction patients with darkening of the face should go to the hospital as soon as possible to clarify the cause of the disease, after diagnosis under the guidance of the doctor for standardized treatment.