The early works by Chipault et al. (3-5) were the precursors of many studies on the antioxidant capacity of a number of plant extracts with potential applications as preservatives in the food, cosmetics, and pharmaceutical industries (6 ±12). The current interest of our laboratory in the biosynthesis of tocopherols in plants and in the identi®cation of alternative sources of natural antioxidants prompted us to develop a method for the evaluation of water-soluble and fat-soluble antioxidant capacity. The phosphomolybdenum method that we propose in this article is now systematically used by us in extensive screenings of samples of very different origins and composition in our search for natural sources of vitamin E and other powerful antioxidants