The most common complication of lumbar puncture is the headache after lumbar puncture. It mostly occurs within 24 hours after lumbar puncture and is considered to be related to intracranial pressure depression, which can be relieved after 5-8 days of rest and, if necessary, the patient can be given intravenous saline. The danger of lumbar puncture can also be seen in brain herniation, especially in encephalitis patients with high intracranial pressure, which can be life-threatening in severe cases. The risk of lumbar puncture in encephalitis can also lead to an increase in intracranial infection in the patient. The bleeding is mainly caused by injury to the arachnoid membrane or the dural sac vein, and the amount of bleeding is relatively small and the clinical symptoms are not obvious. Therefore, lumbar puncture for encephalitis must exclude the patient’s contraindications before giving the patient a lumbar puncture.