Free radicals that appear during physiological processes may lead to apoptosis in some pathological conditions when antioxidant capacity of the tissue is surpassed. Additionally, free radicals are involved in the control of apoptosis; antioxidant agents suppress apoptosis induced by a variety of stimuli. The possibility that apoptosis is regulated by modulation of the levels of free radicals is discussed. (C) 1996 Academic Press, Inc.