Lumbar puncture to draw cerebrospinal fluid can check whether the composition of cerebrospinal fluid is normal or not, and also can assist in reducing intracranial pressure. 1. Checking the composition of cerebrospinal fluid: after lumbar puncture, cerebrospinal fluid can be withdrawn, and then determine whether there is intracranial infection through the number of cells as well as the number of proteins and the number of ions in the cerebrospinal fluid, and then clarify whether there is inflammatory cerebrospinal fluid, traumatic hemorrhage and spontaneous hemorrhage and other diseases. 2. Reduce intracranial pressure: When doing lumbar puncture, extracting cerebrospinal fluid can also help reduce intracranial pressure, alleviate dizziness, headache and other symptoms caused by increased intracranial pressure, and at the same time help control intracranial pressure edema. However, lumbar puncture to draw cerebrospinal fluid is a certain risk, must be carried out under the guidance of a professional doctor.