Chronic subdural hematoma, as the name implies, is a condition that occurs chronically, but can also be dangerous with acute attacks. Chronic subdural hematoma occurs with the following characteristics: 1. It tends to occur in the elderly. The elderly tend to have brain atrophy and the subdural space often appears wider. 2. History of trauma is not obvious. It is generally believed that chronic subdural hematomas are often still caused by head trauma, but this trauma is often relatively mild, or the patient and family simply cannot recall having suffered trauma within the first few months. 3. Easy to misdiagnose. Patients with chronic subdural hematoma often have atypical symptoms, with some patients thinking they have a “cold” because of dizziness and headache, and some having difficulty moving their limbs, thinking they have a brain infarction. The diagnosis of chronic subdural hematoma is easy, and the key is to do a head CT, which can usually make a clear diagnosis. The preferred treatment is drilling and drainage under local anesthesia, which is less invasive and can successfully resolve the problem in the majority of patients. A small number of patients need general anesthesia to clear the hematoma, and this method is relatively more traumatic. After surgery, it is important to lie down for a longer period of time to facilitate the absorption of residual hematoma and also to prevent recurrence.