Polyphenols are important secondary metabolites of plants which provide defense against harmful radiations, infections and other damages caused by insects and animals. This strategy of the plant is mainly considered by the plant scientist for the growth and yield of many agro based products. Almost all the plants in the earth do have these wonderful chemicals at different concentrations at the range of safe to lethal for human consumption. Hence, it plays a crucial role in food industries and nutraceuticals. There are hundreds of different chemical compounds found in this category have numerous therapeutic actions on human health. Activities of these chemicals in animals and human have been proved against physical and mental stress, degenerative diseases, aging, cancer and many metabolic dysfunctions. This review has integrated information of different sectors to understand the relationship and for the availability under a single umbrella. This book covers recent information available from internet resources and research articles. The references and links provided in this book are obtained from open sources which will facilitate the people, students and researches for easy access.