Multiple sclerosis (MS) is a chronic inflammatory disease characterized by central nervous system (CNS) lesions that can lead to severe physical or cognitive disability as well as neurological defects. Although the etiology and pathogenesis of MS remains unclear, the present documents illustrate that the cause of MS is multifactorial and include genetic predisposition together with environmental factors such as exposure to infectious agents, vitamin deficiencies, and smoking. These agents can trigger a cascade of events in the immune system which lead to neuronal cell death accompanied by nerve demyelination and neuronal dysfunction. Conventional therapies for MS are based on the use of anti-inflammatory and immunomodulatory drugs, but these treatments are not able to stop the destruction of nerve tissue. Thus, other strategies such as stem cell transplantation have been proposed for the treatment of MS. Overall, it is important that neurologists be aware of current information regarding the pathogenesis, etiology, diagnostic criteria, and treatment of MS. Thus, this issue has been discussed according to recent available information. Subtypes of MS are considered important not only for prognosis but also for treatment decisions and include relapsing remitting MS (RRMS), primary progressive MS (PPMS), secondary progressive MS (SPMS), and progressive relapsing MS (PRMS). RRMS is the most common subtype (approximately 87%) which characterized by umpire- datable acute attacks followed by periods of remission (3). During RRMS, inflammatory attacks on myelin and nerve fibers occur. Activated immune cells cause lesions in the CNS which generate symptoms of visual impairments, tingling and numbness, episodic bouts of fatigue, intestinal and urinary system disorders, spasticity, and learning and memory impairment. Approximately 10-15% of MS patients are diagnosed with PPMS which largely affect the nerves of the spinal cord. PPMS patients tend to have fewer brain lesions. Induced symptoms include problems with walking, weakness, stiffness, and trouble with balance. Nearly 65% of patients with RRMS will subsequently develop SPMS which is considered the second phase of this disease. Many individuals experience increased weakness, intestinal and urinary system disorders, fatigue, stiffness, mental disorders, and psychological impairment.