Based on their potent antioxidant properties, the possible exploitation of natural phenolic compounds as food supplements as well as functional ingredients in the food and cosmetic industry is gaining more and more attention. This book contains original research articles and a review reporting innovative applications of natural phenolic compounds in the field of nutrition and biomedicine, as active ingredients for the prevention of oxidative-stress-related diseases, and as additives in smart food packaging, biomedical devices, and cosmetic products. The growing importance of agri-food wastes as easily accessible sources of phenolic compounds as well as of synthetic derivatives of natural compounds with improved antioxidant properties is also highlighted. Finally, novel technologies to improve extraction yields, stability, bioavailability, and delivery of antioxidant compounds for healthcare products or for skin applications are described.