Use of medicinal plants is as old as human civilization and continuous efforts are being made to improve medicinal plants or produce their products in high amounts through various technologies. About 200,000 natural products of plant origin are known and many more are being identifed from higher plants and microorganisms. Some plant-based drugs have been used for centuries and there is no alternative medicine for many drugs, such as cardiac glycosides. However, natural products research was sidelined to pave the way for com- natorial chemistry, which was expected to produce large numbers of synthetic compounds for high-throughput screening (HTS). This line of work has failed to deliver desirable results. Moreover, it is not possible for all pharmaceutical companies and institutions to adopt costly HTS technology. Therefore, medi- nal plants and their bioactive molecules are always in demand and are a central point of research. While planning this book, we endeavored to incorporate - ticles that cover the entire gamut of current medicinal plants research. The aim of this book was to review the current status of bioactive molecules and medicinal plants research in light of the surge in the demand for herbal medicine. The chapters focus on bioactive molecules (e.g., stilbenes and p- toestrogens) and on medicinal plants as a whole (e.g., Bacopa monnierie). We hope that this book will be useful for researchers in academia, industry, and agriculture planning.