Research on antioxidant content of food and beverages has been increasing particularly due to the belief that eating foods and beverages with high antioxidant content, including fruits, vegetables, whole grains, tea, coffee, wine and cocoa, is synonymous with having good health. Indeed, high total antioxidant capacity (TAC) of foods has been associated with biomarkers of lower oxidative stress and considered a protective factor for various chronic diseases, such as cardiovascular disease, diabetes and certain types of cancers. Development of comprehensive marketing and advertising campaigns for antioxidant-rich foods can help the general population to become aware of the benefits of consuming these types of food. Moreover, defining a standardized TAC method and a reference TAC database would help to compare TAC of different foods and beverages. For this reason, the first part of this chapter focuses on the different methods for measuring TAC and the parameters that influence TAC in food and beverages, such as storage, preservation and cooking methods. The second part of the chapter is devoted to demonstrating the utility of TAC data in food science, nutrition and biomedical research.