Natural products have dominated our lives since ancient times. Today, they are an inexhaustible source of new medications for disease treatment. The practice of evaluating bioactive compounds extracted from natural sources has also advanced significantly, prompting a need to understand current methods to identify and evaluate them. This book covers basic scientific aspects of preclinical research on natural products for specific conditions and diseases. These include aging, gynecological disorders, inflammatory disorders, renal disorders and cardiovascular disorders. Each of the 10 book chapters give a structured overview on preclinical methods on the etiology of diseases, natural products as the materials for the bioassays, extract types, concentration of the extracts/compounds for in vitro and in vivo assays, preparation of the test materials, application of the test materials, step-by-step methods and related calculations. The book is intended as a quick reference for natural product researchers, pharmacists and postgraduate students in pharmacognosy. Medical doctors working in preclinical research on natural products will also benefit from the information provided.