Free radicals, molecules or atoms with unpaired electrons, are unstable and can form new compounds. They can come from inside the body (endogenous) or from outside (exogenous), and their overabundance leads to oxidative stress. If the body is unable to neutralise them, these radicals increase oxidation in cells, causing tissue damage. To mitigate this damage and prevent degenerative diseases, the consumption of natural antioxidants is essential. These compounds neutralise free radicals, protecting cells, proteins and fats. Their structure donates electrons to free radicals without altering their function, thus stopping the free radical chain reaction. For three decades, numerous studies have investigated free radicals, oxidative stress and the role of antioxidants in health. This book delves into these areas and provides the reader with a thorough understanding of their interplay.