A bioactive compound is a type of chemical that can be found in plants and specific foods including nuts, whole grains, fruits, oils and vegetables in small amounts. The actions of bioactive compounds in the body can encourage good health. These compounds are studied in pharmaceutical sciences to treat a variety of medical conditions. Tannins, lycopene, lignan, indoles and resveratrol are few examples of bioactive compounds. Natural products derived from bacteria, marine life, plants, fungi, animals and other organisms are a valuable resource for drug discovery and development. Bioactive natural products have a wide range of biological activities that are beneficial to human health, such as anti-inflammatory, anticancer, antibiotic, biofilm inhibitory effects, antifungal and immunosuppressive properties. Different natural products from both terrestrial and marine organisms have been identified and characterized, as these products have unique chemical structures and noteworthy biological functions. This book aims to understand the role of bioactive natural products in drug discovery. Researchers and students engaged in drug discovery will be assisted by it.