Overly exuberant and exaggerated past expectations and claims of the free radical theory have been quieted by extensive randomized, double-blind, controlled human studies. A half century of data demonstrates its lack of predictability and it has not been validated by the scientific method. Widespread use of antioxidants has failed to quell the current pandemic of cancer, diabetes, and cardiovascular disease or to stop or reverse the aging process. Electronically modified oxygen derivatives contribute to the modulation of cellular redox status, which is of primary importance in disease prevention and homeostasis.