Antioxidants are free radical scavengers which provide protection against free radicals that causes various pathological conditions such as ischemia, inflammation and aging process. There are some enzymatic and some non-enzymatic antioxidants present in the body which provide protection against oxidative damages caused by reactive oxygen species. Some enzymes which provide protection against oxidative stress produced by imbalance between free radicals and ability of body to counteract or detoxify their harmful effects through neutralization by antioxidant are Glutathione, Glutathione Reductase and Glutathione peroxidase.