Methods: The study will be authorized by the Ziv Helsinki Committee. Informed consent and questionnaire will obtained from all subjects before study entry. We will examine 120 volunteers in a blind fashion, including 60 MS patients diagnosed by a neurologist based on clinical, laboratory and MRI findings. Patients will be evaluated according to EDSS score. The control group will include 50 age and gender matched healthy volunteers and 10 more patients with unrelated neurological diseases. Inclusion criteria: Age 18-60; Exclusion criteria: Other diseases, pathologies, or immune system disorders. Here, we will examine expression of different fatty acids in the serum and in erythrocyte samples; Monitor mitochondrial transmembrane potential as marker for the mitochondria general function.