This book presents a general overview of herbal drugs, including chemical characters in plant taxonomy and the biodiversity of plants. Providing the latest scientific information on plant drug research including a few crucial leads in herbal drug research, he takes up in detail the research done in medicinal plants, showcasing aspects of ethnopharmacology: he probes the history of medicinal plants and significance of plant drugs with reference to some of the major diseases like tuberculosis, cancer and AIDS and ocular, lover and cardiovascular disorders. He discusses the potential health benefits of natural antioxidants, garlic and fig plants. He also views some of the important phytopharmacological features of secondary metabolites focusing on flavonoids, chemistry and biological significance of xanthones.