Oxidative stress is essentially an imbalance between the production of free radicals and the ability of the body to counteract or detoxify their harmful effects through neutralization by antioxidants. Oxygen by-products are relatively unreactive but some of these can undergo metabolism within the biological system to give rise to these highly reactive oxidants. Not all reactive oxygen species are harmful to the body. Some of them are useful in killing invading pathogens or microbes.Oxidative stress leads to many pathophysiological conditions in the body. Some include neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease, genetic mutations and cancers, chronic fatigue syndrome, fragile X syndrome, heart and blood disorders, atherosclerosis, heart failure, heart attack and inflammatory diseases.