The sudden appearance of drowsiness in the elderly should firstly exclude organic brain lesions, check the cranial MRI, which may be caused by brain tumors, mental disorders, hypoglycemia, cerebrovascular diseases, etc. The details are as follows: 1. Brain tumors: Patients may appear drowsy in the early stage, and may also have headache, nausea, vomiting and other symptoms. 2. Mental disorders: For example, when there is depression, it may If the patient is depressed, not interested in anything, self-evaluation ability is reduced, and in serious cases, the desire for light life may arise, causing the patient to be depressed and drowsy. 3, hypoglycemia: when the patient has low blood sugar, it may also cause, if necessary, to measure the blood sugar. In normal people, if the blood sugar is lower than 3.9mmol/L, it is often called hypoglycemia, which should be treated with sugar supplementation in time. severe hypoglycemia may cause hypoglycemic encephalopathy, and even cause brain cell dysfunction. 4, cerebrovascular disease: for example, cerebral hemorrhage and cerebral infarction can occur, and brain nuclear magnetic examination can be clarified.