By Mindy

A concise, nimble, well-written, highly organized and readable text that expertly explains the concepts between the chemical constituents of plants and their effects on human physiology. This is a must read for herbalism practitioners and their students.

As a physician, I admit I can sometimes get a bit reductionist in my thinking about herbs.  I want to know how the plants work…what are the active compounds? what do those compounds do? what biological pathways do they effect?  With a background in toxicology, I would love to see a full GC-MS profile on each herb, and all the detected compounds boxed in on a biochemical chart of human physiology. Dr. Andrew Pengelly, in an exceptionally well-organized and concise manner, attempts to do just that with prose in The Constituents of Medicinal Plants: An Introduction to the Chemistry and Therapeutics of Herbal Medicine (2nd Edition, 2004).

Click on the photo link to to buy this book and we will receive a small commission at no extra charge to you!

First off, this book is amazingly small, 172 pages, about 9″ x 6″, and with a width of little over a half inch! This is actually a very good thing when it comes to what is essentially an organic chemistry text book. Glossy soft cover, well-constructed, and light weight, it is the type of book you actually could bring to bed with you.

An introductory chapter of 12 pages offers a primer, or maybe better put a review, on organic chemistry. This book probably would not suffice for someone with no chemistry knowledge whatsoever, however a high school level class would probably be enough science training to be able to follow along.  The Constituents of Medicinal Plants does a fine job of balancing between too much and too little information.

The remainder of the book is separated by chemical classes, including chapters on phenols, polyphenols, glycosides, terpenes, triterpenoids and saponins, essential oils and resins, fixed oils and alkamides, polysaccharides, and alkaloids. Those chapters are further subdivided into more specific chemical constituents.

The entry for each individual chemical constituent contains a drawing of the chemical structure, a general description on the chemical class, its known physiological actions, and the plants that it can be found in. Amazingly, Dr. Pengelly is able to present this information in a readable, highly digestible, and remarkably informative manner. For such a dry topic, The Constituents of Medical Plants is actually fun to read. A part of this has to do with the visual presentation of the material. The pages are well-organized and not overly cluttered, which I find really helps in processing the technical information.

Deficits? This is a book is introductory. It does a fantastic job of providing an overview of the plant chemical categories and their physiological activities. It can, and should, be read cover-to-cover. While the material is robust, it is not by any means comprehensive, and probably should not be considered a desk reference for complex chemistry. Another deficit is that not enough information is actually known about the interactions between plants and humans; the science simply does not exist. Dr. Pengelly patches these pieces together eloquently, trying to build authentic (if somewhat rickety) bridges with the information that is available.

In short, I love this book. It wets the whistle of any herbalist who is willing to look down the reductionist hole, wanting insight into the hows and whys of herbalism.

Check out our 2-part guide on Beginning Foraging !

Note: The Walking Herbalist is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to This means that Marc will receive a small commission for each purchase on Amazon that you make after linking to it from this website. 

The Walking Herbalist has no affiliation of the authors or the publishers of this book at the time of the writing of this review. We purchased our own copy of this book for our own private use. This review is simply here to help our readers put together their own herbalism library, and other than possible commissions as an affiliate, we receive no compensation for this. 


  • Chelsey Baranczyk

    February 24, 2016 at 8:09 am Reply

    Great thorough book review! I think you’ve convinced me to add this to my list of books to pick up! Please continue the book reviews! I like to hear others honest opinions about them before I decide to purchase them!

    • The Walking Herbalist

      February 24, 2016 at 10:02 am Reply

      Thanks for the note, and am glad the reviews are helpful. Dr. Pengelly really did put together a good book with this one, wr think. One of our sly side missions is to try to get people to invest in books. We just tracked down an English version of Dioscorides…it’s nearly impossible to get! We worry about the loss of all this great knowledge to the computer. Thanks for the comment and the retweet!

Post a Comment