In the early development of modern medicine, biologically active compounds from higher plants played a vital role in providing medicines to combat pain and disease, and most of these were culled from plants traditionally used for that purpose in one culture or another. Even now, search for bioactive molecules from nature (plants, animals, microflora) continues to play an important role in fashioning new therapeutic agents. Besides, in the last three decades or so, a new trend in the preparation and marketing of drugs based on medicinal plants has become increasingly important in several European countries. These preparations, labelled herbal drugs or phytomedicines are carefully standardized, and their efficacy and safety for a specific application demonstrated, and are dispensed just like the allopathic preparations. Additionally, in several countries traditional medicine is still in vogue, and in fact, has been gaining more acceptability for treatment of chronic ailments. This is especially true for countries like India and China, which have a long tradition of fairly well-organized traditional therapy. With this background, it is not surprising to see a renascence in the exploration of medicinal plants by more incisive modern techniques of chemical and biological sciences, available now. Traditional Ayurvedic therapeutic formulations draw on an impressive array of plants, and several of these had attracted the attention of investigators from mid- 1950s, and highly significant amount of research results have been published in various peer-reviewed international journals. Though, several books on Ayurvedic plant drugs have been published, there was not a single cogent one, aimed primarily at evaluation of therapeutic claims in the present-day context. This void motivated the present author to write and get published 'Prime Ayurvedic Plant Drugs ' in 2006. Since then, highly meaningful new research results covering these and a few additional Ayurvedic medicinal plants have been published. This necessitated the publication of an updated Second Edition of this book. In this revised and enlarged edition, not only highlights of new medicinally valuable information that emerged since 2005, has been incorporated, but 14 new prime Ayurvedic plant drugs, which attracted the attention of research workers, have also been included. Besides updating other sections, including the General Introduction, another Annexure (no. 4) covering Plant-wise Activities, has been added. Both Annexures 3 and 4 depict medicinal/therapeutic activities confirmed by modern scientific methods, and in both of these, clinical confirmation has been highlighted (green print).