en Neurology Review Multiple sclerosis (MS) is one of the most important debilitating diseases in which the myelin sheaths of nerve cells in the brain and spinal cord are damaged. In this review, we aimed to review the pathophysiology of MS. This impairment causes ability disorder of the parts of the nervous system which are responsible for communication, leading to different symptoms including physical and psychological problems. This study was conducted through a Narrative review using keywords including Multiple Sclerosis, Epidemiology through Search in International Scientific Databases, including: PubMed, Web of Science, Google Scholar and Scopus, and Persian scientific databases including: Barakatkns Knowledge System, Academic Jihad Database, Iranian Medical Library (Medlib), Magiran Database, Knowledge Reference (Civilica), and a search was done on the World Health organization website. In this review study, using keywords such as "pathophysiology" and "multiple sclerosis". Multiple Sclerosis, Pathophysiology, Nervous system 15 8 http://tbsrj.mazums.ac.ir/browse.php?a_code=A-10-3490-1&slc_lang=en&sid=1 Ali Alizadeh Khatir alizadeh.ali83@yahoo.com 100319475328460029301 100319475328460029301 No Department of Neurology, Mobility Impairment Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran. Seyed Mohammad Masood Hojjati hojjatiseyedmohammadmasood@gmail.com 100319475328460029302 100319475328460029302 Yes Department of Neurology, Mobility Impairment Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran. Alijan Ahmadi Ahangar ahmadiahangaralijan@yahoo.com 100319475328460029303 100319475328460029303 No Department of Neurology, Mobility Impairment Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran. Hoda Naghshineh hodanaghshineh@yahoo.com 100319475328460029304 100319475328460029304 No Department of Neurology, Mobility Impairment Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran. Payam Saadat sepanta1968@yahoo.com 100319475328460029305 100319475328460029305 No Department of Neurology, Mobility Impairment Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran.