MS is the abbreviations of Multiple Sclerosis that refers to chronic degenerative disease of the central nervous system in which gradual destruction of myelin occurs in patches throughout the brain or spinal cord (or both), which interferes with the nerve pathways, causing muscular weakness, loss of speech and coordination, and visual disturbances.

It is the most common potentially disabling disease of the central nervous system affecting young adults. (see Multiple Sclerosis) In most patients of MS, the disorder moves through characteristic phases of attacks which recover, episodes leaving persistent deficits and then slow progression. This natural history usually evolves over many years and life expectancy is not significantly reduced. The onset of MS is usually in early adult life but children and adolescents can be affected.