Antioxidants are the molecules which inhibit the oxidation of other molecules. Free radicals are produced during oxidation which may damage cells and may affect health to extreme levels. Antioxidants are available in natural as well as in synthetic forms. Antioxidants are copious compounds mostly found in fresh fruits and vegetables, and their roles in the deterrence of degenerative diseases are promising. Generally, natural antioxidants are preferable by the consumers. Synthetic antioxidants are generally compounds having phenolic structures of assorted degrees of alkyl substitution. Antioxidants in human body may play an important role as these can amend cellular oxidative status and prevent protein, DNA and membrane lipids from damage and reduce the risk of several chronic diseases like cardiovascular diseases and cancer. This book covers the information regarding importance of antioxidants, classification, benefits for healthy life, mechanisms, different antioxidants for lifesustainability, extraction methods for antioxidants and their detection methods.