Fainting and waking up in the elderly is usually considered a syncopal episode in clinical practice. Common causes include cerebral arteriosclerosis, blood volume insufficiency and cardiogenic syncope. 1. Cerebral arteriosclerosis: when patients have symptoms of cerebral arteriosclerosis, there may be poor blood supply to the brain, especially ischemia in the posterior circulation. When the blood supply to the brain stem is interrupted, it will cause transient loss of consciousness and the phenomenon of fainting. 2. Insufficient blood volume: fainting may be caused by insufficient blood volume, for example, when the patient is suffering from diarrhea, nausea, vomiting, bad eating, etc., it will trigger insufficient blood volume and fainting may occur. 3. Cardiogenic syncope: it is also a more important cause of syncope. For example, syncope caused by arrhythmia, bradycardia, abnormal function of sinus node, tachycardia, supraventricular tachycardia, or syncope caused by organic cardiovascular diseases. Therefore, if the old man has fainted and woke up again, he should go to the hospital in time to clarify the cause of the disease and get treatment as soon as possible so as not to delay the condition.