Free radicals, which are atoms that have an unpaired elec- tron, are both essential to life and harmful. The body pro- duces oxygen free radicals as a natural part of making ener- gy (in the form of ATP) in most cells. Because making energy and thus free radicals cannot be avoided, the body has evolved a variety of defenses against free radicals known as antioxidants. These quench or neutralize the free radicals after they are produced, allowing cells to make ATP energy without building up toxic levels of free radicals. Natural antioxidants include such familiar substances as vitamin C, vitamin E, coenzyme Q10, superoxide dismutase, and cata- lase. The problem arises when the body comes under free radical assault above and beyond the burden from normal metabolic processes. When the air, water, and food all con- tain significant sources of free radicals, the body now has to quench these or face cellular damage and disease. Chronic inflammation causes a great increase in free radicals because immune cells produce free radicals to damage and kill infec- tious organisms and cancer cells. Additionally, white blood cells are very active, thus they require and produce a lot of energy and free radicals. Medicinal plants contain numerous types of vitamin and non-vitamin antioxidants that can bol- ster the body's defenses against free radicals.