An important field of research today is the control of ‘redox’ status with the properties of food and food components. Natural antioxidants present in the diet increase the resistance toward oxidative damages and they may have a substantial impact on human health.Dietary antioxidants such as ascorbates, tocopherols and carotenoids are well known and there is a surplus of publications related to their role in health. Plant phenols have not been completely studied because of the complexity of their chemical nature and the extended occurrence in plant materials.Extensively studied sources of natural antioxidants are fruits and vegetables, seeds, cereals, berries, wine, tea, onion bulbs, olive oil and aromatic plants. Attempts are also made to identify and evaluate antioxidants in agricultural by-products, ethnic and traditional products, herbal teas, cold pressed seed oils, exudates resins, hydrolysis products, not evaluated fruits and edible leaves and other raw materials rich in antioxidant phenols that have nutritional importance and/or the potential for applications in the promotion of health and prevention against damages caused by radicals.