Syncope is a sudden onset of temporary, widespread cerebral blood supply deficit resulting in a brief loss of consciousness. It is mostly caused by somatic factors, but can also be secondary to impaired blood circulation to the brain. The elderly, sedentary after intense exercise, etc. are prone to fainting. What causes syncope? What are the diseases that cause syncope? The classification of the causes of syncope is not uniform. Generally, syncope is classified into different types according to the cause. These include: 1, vasodilatory syncope; 2, cardiogenic syncope; 3, cerebral syncope; 4, pharmacogenic syncope; 5, metabolic syncope; 6, syncope caused by physical factors; 7, others. Some scholars also briefly summarize them as: cardiogenic syncope, non-cardiogenic syncope and unexplained syncope. According to the etiology, syncope can be divided into 4 major categories: 1, hypotensive syncope; 2, cardiogenic syncope; 3, cerebrovascular syncope; 4, multifactorial and other types of syncope.