The Complete Guide to Herbal Medicines. Charles W. Fetrow, Juan R. Avila. Springhouse Corporation, 2000, 638 pp. illustrated softcover, ISBN 1-58255-062-X $39.95 (plus S/H) Also available from Pocket Books, a division of Simon & Schuster, 2000, 716 pp., softcover, ISBN 0-7434-0070-4 $6.99 (Not offered in the ABC Catalog).
We need to clean up the pollution in herbal information, much of which is industrial, though a sizable amount is also generated by academia. I refer to The Complete Guide to Herbal Medicines, a reference guide compiled by two Pharm.D.s with the help of 73 contributors and consultants, 50 of whom are also Pharm.D.s, the remainder being M.D.s, Ph.D.s, R.Ph.s, and R.N.s. Despite these credentials, misinformation and false statements jump out at you! They have done their own professions, related professions, and the general public a huge disservice.
For example, under "Wild Yam" is this outrageous statement: "Wild yam also contains a steroid hormone called dihydroepiandrosterone (DHEA, which is actually dehydroepiandrosterone), which may be useful in treating various diseases." Wild yam does not contain DHEA. It does, however, contain steroids such as diosgenin and others, which can be converted to steroid hormones (e.g., DHEA) by microbial transformation and/or chemical modification. If yams contained DHEA, progesterone, or other steroid hormones, Syntex (the company that practically revolutionized the steroid hormone industry) would not exist. The upsetting question is, why would a major publisher produce such a guide without having it reviewed by qualified experts?
Despite the authors’ intention "to give you the scientific facts about herbs—not to confuse or distract you with the myths or folklore that surround them," they have done just the opposite: by indiscriminately listing diseases for which each herb is allegedly used to treat.
For example, according to their "Aloe" entry, people use "aloe" for the following conditions: acne, AIDS, arthritis, asthma, bleeding, blindness, bursitis, cancer, common cold, colitis (inflammation of the large intestine), constipation, depression, diabetes, glaucoma, hemorrhoids, lack of menstruation, seizures, skin conditions (abrasions, cuts, irritations, minor burns, frostbite, sunburn, and wounds), stomach ulcers, and varicose veins. The authors do not indicate which are legitimate uses and which are not. Without this information, we may as well add another score from various outrageous marketing publications.
And what is "aloe" anyway? The authors seem clueless, writing, "It comes from the aloe vera plant (also called Aloe barbadensis, A. vulgarisms hybrids, A. africana, A. ferox, A. perryi, and A. spicata). The plant’s large, bladelike leaves are the source of aloe vera gel. Aloe preparations for oral use contain either the colorless juice that comes from plant’s top layer or a solid yellow latex obtained by evaporating the juice." First of all, what is the "It" they refer to? The gel or the drug aloe? What is the plant’s "top layer"? Is it the tallest part of the plant, like the tip of the flower stalk? Also, how does one obtain a "solid yellow latex" by "evaporating the juice"? And what juice? Clearly, the authors are confused. If they had been even half diligent, they would have readily found (and read) numerous reputable publications, including a review by Grindlay and Reynolds,1 which clearly distinguishes the two kinds of "aloe": (1) aloe vera gel, the mucilaginous bland-tasting liquid from the center of the aloe vera leaf; and (2) the drug aloe, the dried bitter yellow latex from specialized (pericyclic) cells just beneath the skin of the leaf. The two are completely different products. The gel is an emollient and its healing properties have made "aloe vera" practically a household word over the past two decades. It is not the drug aloe. The latter, simply called "aloe" in the USP, is the dried bitter yellow latex that has cathartic properties. It is normally used in laxative preparations, though sometimes also in sunscreen preparations, and (erroneously) in place of aloe vera gel in certain cosmetics. This is why it’s so important for a "complete guide" to provide a clear distinction.
The sad thing about this work is that you don’t have to make an effort to find misinformation, false conclusions, illogical thinking, and plain expressions of ignorance. They are in every single entry I have scanned so far, ranging from a few minor ones to numerous major blunders!
On page 1, under "Common drugs made from plants," the first drug described is aspirin as from white willow bark and meadowsweet plant. The fact: aspirin is the acetate of salicylic acid (or acetylsalicylic acid); it does not occur in those plants. Salicylic acid is used in the synthesis of aspirin.
Then, comes this: "Indian herbal tonics can lead to lead poisoning." How can such a statement be made at all, especially by professionals supposedly trained to be nonbiased in disseminating information? I am sure they wouldn’t publish statements such as "Synthetic analgesics can lead to kidney damage" or "Synthetic analgesics can lead to heart failure," even though these latter statements have as much truth or falsehood (depending on your view) as the first.
Immediately following the "Potentially Dangerous Herbs" list, the authors state, Some herbs and plants have value not just for their active ingredients but for other substances they contain, such as:
volatile oils (used in aromatherapy)
glycosides (sugar derivatives)
alkaloids (bitter organic bases containing nitrogen)
bioflavonoids (colorless substances that help maintain collagen and blood vessels).
What were they thinking when they wrote this? How do they define "active ingredients"? Do they mean none of the above compounds are biologically active? The fact is, many of the above classes of compounds have strong pharmacological effects, especially the last four categories—volatile oil components (eugenol, methylsalicylate, thymol, eucalyptol, etc.); glycosides (ginsenosides, aloins, cascarosides, sennosides, rutin, glycyrrhizin, etc.); alkaloids (caffeine, cocaine, morphine, codeine, berberine, ephedrine, etc.); and bioflavonoids (countless, like those in ginkgo, licorice, hawthorn, green tea, etc.). And, where do they get the notion that bioflavonoids are colorless substances? In fact, many are colored like rutin (a yellow flavonoid glycoside), which appears to be the one they had in mind ("help maintain collagen and blood vessels").
On page 7, under "Tinctures and extracts" the authors again show their ignorance regarding a major aspect of herbal medicine. Here they write, "An herb placed in alcohol or liquid glycerin (to distinguish it from solid glycerin?) is called a tincture or an extract. (Tinctures contain more alcohol than extracts.) Alcohol draws out the herb’s active properties, concentrating them and helping to preserve them. Alcohol is cheap, is easily absorbed by the body, and allows the herb’s full taste to come through. Alcohol-based tinctures and extracts have an indefinite shelf life … ." The first sentence is a typical example of their muddy, illogical thinking and ignorance. By this definition, a piece of dandelion root in my hand is "dandelion root," but after I have placed it in alcohol or glycerin, this same piece of herb now becomes either "dandelion root tincture" or "dandelion root extract"! And tinctures are not distinguished from extracts by the amount of alcohol!
Here is the technical truth: a tincture is simply one type of extract, of many, including fluid extract, solid (pillular) extract, powdered extract, and native extract. Extracts can be prepared by using various solvents (or menstrua) including alcohol, aqueous alcohol, water, and glycerin, and they can be any strength from weak (e.g., infusion) to highly concentrated (native extract). Tinctures, specifically, are alcoholic or hydro-alcoholic extracts containing normally 10% and sometimes 20% of the crude herb’s equivalence, which means 10g or 20g of herb are used to make 100mL of the finished tincture.
This Complete Guide is the worst publication by alleged professionals I have ever come across. If there were such a thing as a "book recall" (as in "drug recall"), this one would fit the bill. Sadly, it will take many years of hard work for knowledgeable professionals to correct the damage done.
—Albert Y. Leung, Ph.D.
This review is condensed from a three-part review published in Leung’s Chinese Herb News, July/August, Sept/Oct, Nov/Dec, 2000; Issues 27–29.
1. Grindlay D, Reynolds T. The Aloe vera phenomenon: A review of the properties and modern uses of the leaf parenchyma gel. J Ethnopharmacol 1986;16:117-51.