Demyelination of the central nervous system, including diffuse demyelination and focal demyelination. In diffuse demyelination, most of them are considered to be caused by chronic cerebral ischemia and hypoxia. Patients usually present with dizziness, memory loss, inattention and thought disorders, and in advanced stages, they may develop cognitive dysfunction and can show signs of dementia. There is no special treatment at this time. Oral oracetam, piracetam and cytarabine can be taken to improve brain metabolism, and blood activating drugs can also be applied, such as oral ginkgo biloba drops and ciprofloxacin may slow down the progress of the disease. If the patient is focal demyelinating, the common disease is multiple sclerosis, and the patient can present with different symptoms, including limb motor dysfunction, sensory impairment, dizziness, balance disorder, and also large and small bowel dysfunction, mainly related to the site of the lesion. Glucocorticoids can be applied in the early stage of the disease, along with nutritional nerve therapy, and the prognosis is generally poor.