Syncope is a sudden, transient loss of consciousness due to temporary ischemia of the brain for various reasons, medically known as “syncope”. Syncope occurs in normal people under special circumstances and is a physiological phenomenon. However, if a person faints frequently or if an older person has fainting spells, it may be pathological syncope and must be examined in a hospital. The common causes of syncope are roughly the following: 1. vasovagal syncope: This is the most common, mostly in young people, and often has a fixed trigger for the attack, such as urination, cough, pain, emotional stress, fear, sweltering weather, strenuous exercise, fasting, etc. Syncope sometimes has no symptoms before the attack and will recover quickly without sequelae. Sometimes blood pressure and/or slowed heart rate may occur, and this syncope can usually be cured by special exercises for most people under the guidance of a doctor, and a few need to be treated with drugs or pacemakers. 2, cardiogenic syncope: refers to syncope caused by a sudden reduction or suspension of cardiac output due to heart disease, mostly caused by arrhythmias and organic heart disease. Common arrhythmias include pathological sinus node syndrome, atrioventricular block and other bradycardia or arrest, and tachyarrhythmias, such as ventricular fibrillation and ventricular tachycardia, which cause syncope due to reduced cardiac output. Organic heart disease, such as acute heart attack, cardiac mucinous tumor, hypertrophic obstructive cardiomyopathy, and congenital cyanotic heart disease, can cause syncope. Cardiogenic syncope is common in the elderly, which lasts for a long time and is dangerous. Elderly people with cardiac disorders should communicate with cardiovascular specialists for treatment and apply pacemakers and implantable cardioverter-defibrillators if necessary. 3, cerebral syncope: It is caused by the circulatory disorder of the blood vessels in the brain or the blood vessels that mainly supply blood to the brain, resulting in a momentary widespread cerebral blood supply deficiency. Most often seen in the elderly, common causes include transient cerebral ischemia, brainstem syncope, aortitis, etc. Preventive measures are to prevent cerebrovascular atherosclerosis, reduce cerebrovascular spasm, regular medication, and regular review. 4, upright hypotensive syncope: Most often seen in the elderly or long-term bedridden people. It is manifested as black fainting before the eyes after a sudden change of position. Preventive measures are to stand up slowly or hold things up, and not to squat for a long time. 5, hypoglycemic syncope, syncope caused by disorders of the internal environment, etc. In short, there are many causes of syncope, vasovagal syncope is the most common, and cardiogenic syncope is the most dangerous. Treatment: During the attack, the syncope should be placed in a supine position or lower limb elevation, which can increase cerebral blood flow. Loosen the collar, turn the head to the side, and contact the hospital for emergency care. If a patient with syncope experiences respiratory and cardiac arrest, out-of-hospital emergency care is required.