The sub-specialty of pharmacy concerned with the study of the medicinal drugs derived from plants and other natural sources is called pharmacognosy. It involves the study of the physical, biological and chemical properties of drugs, as well as the search of new drugs from natural sources. The alternative and pseudoscientific practices of using unrefined plant or animal extracts for the purpose of treatment is called phytotherapy. Herbal medicines are used to treat patients suffering from chronic conditions or diseases like ashtma, cancer, diabetes, etc. This book traces the progress of pharmacognosy and phytotherapy, and highlights some of their key concepts and applications. It strives to provide a fair idea about these disciplines and to help develop a better understanding of the latest advances within these fields. This book includes contributions of experts, which will provide innovative insights into these fields.