The aim of this study is to investigate the effect of coenzyme Q10 supplementation on serum level of antioxidant factors in multiple sclerosis patients. In this parallel randomized controlled trial, 50 men and women with multiple sclerosis will be recruited from center of multiple sclerosis of Sina hospital of Tehran university of medical science. Inclusion criteria are adults 18-51 years old, able to provide informed consent and diagnosed with relapsing remitting MS. Exclusion criteria are: MS exacerbation during of study, systemically administered corticosteroids during the study, pregnant or breast-feeding, other significant health problem (e.g. active coronary heart disease, liver disease, pulmonary disease, diabetes mellitus and other autoimmune disease) that might increase the risk of subject experiencing adverse events; consumption of vitamin, mineral and antioxidant supplement 30 days before study entry, any condition which would make the subject, in the opinion of the investigator, unsuitable for the study and compliance less than 70%. Prior to the study, the subjects will be required to complete 3-days 24-hour dietary recall. Diets will be analyzed for calorie and macronutrients and copper, iron, zinc and manganese content. Intervention group receives 500 mg of coenzyme Q10 as 2 capsules and other group receives 2 placebo capsules. Blood samples will be obtained after an overnight fast before and after the study.