This book consists of original or review articles, provides an update and unique source of information for all those interested in the fundamental, biochemical processes of the latest and emerging topics and techniques concerned with the therapeutic uses of medicinal plants. Although we assume that most readers have at least an introductory knowledge of role of plants in medicine, yet we have attempted to compile and edit the invited chapters written by subject experts in a way that even a stranger to this field could easily understand and comprehend. Moreover, we hope that it will also be useful to working scientists in search of a guide to help them pick their way through a vast field of knowledge.