Pengelly's user friendly text will encourage educators in medical science to consider using this material in the complementary medicine/nutraceuticals areas. This unique book explains in simple terms the commonly occurring chemical constituents of medicinal plants. The major classes of plant constituents such as phenols, terpenes and polysaccharides, are described both in terms of their chemical structures and their pharmacological activities. Identifying specific chemical compounds provides insights into traditional and clinical use of these herbs, as well as potential for adverse reactions. Designed as an undergraduate text, the first edition of this book became an essential desktop reference for health practitioners, lecturers, researchers, producers and anyone with an interest in how medicinal herbs work. This edition has been extensively revised to incorporate up-to-date research and additional sections, including an expanded introduction to plant molecular structures, and is destined to become a classic in the literature of herbal medicine.