The book is an introduction to medicinal plants and their use in traditional system of medicine, current status of medicinal plants and natural products isolated thereof and isolation of phytochemicals/bioactive molecules from these plants which act as therapeutic agents. The use of traditional medicine and medicinal plants in most developing countries on normative basis for the maintenance of good health has been widely observed. Medicine, in several developing countries, using local traditions and beliefs, is still the mainstay of health care.