Since ancient days, human beings have been suffering from various diseases. To our rescue, nature has provided a rich storehouse of herbal products to cure all ailments of humankind. Such products are widely used as therapeutic agents for different ailments such as hypertension, mental illness, cancer, leprosy and skin disorders. The ever increasing threat to human life by both neoplastic diseases and AIDS makes the pursuit of antitumor, antiviral and antimicrobial compounds take on a compelling urgency. Sensing the importance and antidisease properties of the medicinal plants, articles of this book have been compiled to give a clear cut picture on the subject, and also help the medical practitioners to keep abreast of the latest developments. This book, first of its kind, is the outcome of concerted efforts of a large number of experts, who have not only recorded their ideas in the form of review articles, but also have shared their thoughts which would be very valuable to the users of this text. The wide coverage, expertise of the contributors and potential for practical use of the contents of this book will be of immense utility and will cater to the immediate needs of the students, researchers, faculty members, and the medical fraternity.