Free radicals generated as byproducts of normal metabolism can damage biologically relevant molecules. When their generation is increased, damage can also be increased, resulting in the development of many pathological conditions. Antioxidant defenses protect the body from the detrimental effects of free radicals. Dietary fruits and vegetables provide a reasonable amount of compounds that act as physiological antioxidants. Although existing knowledge does not allow a final and conclusive assessment of the relevance of antioxidants for health, it does provide the basis for its rational consideration. This paper addresses the specific aspects of antioxidant supplementation in health and disease.