Coughing suddenly fainted, be alert to the occurrence of vasovagal syncope, cough syncope syndrome, chronic obstructive pulmonary disease. 1. Vasovagal syncope: coughing can induce vasovagal syncope, causing transient vascular bed dilatation, decreased return blood volume, decreased cardiac blood loss, decreased blood pressure resulting in insufficient cerebral blood supply. It can be manifested as sudden fainting. 2. Cough syncope syndrome: transient loss of consciousness occurs when coughing, but it can be recovered by itself without leaving sequelae. The mechanism of its occurrence is that when coughing, chest pressure rises, venous return blood volume decreases, cardiac output decreases, and transient cerebral ischemia occurs, leading to syncope. It is also believed that when coughing, the cerebrospinal fluid pressure rises and produces a shock effect on the brain, which may be manifested as sudden syncope. 3. Chronic obstructive pulmonary disease (COPD): If the cough is more intense, there will be temporary hypoxia, manifested as sudden fainting. Fainting is not entirely caused by coughing, but may also cough complication of other diseases, if coughing suddenly fainted, it is recommended to consult a doctor in a timely manner, to clarify the cause of the disease, and comply with the doctor’s instructions for treatment.