Cautions About Herbal Medicine

There is nothing about herbs that automatically makes them non-toxic just because they are natural. Ever hear of deadly nightshade or poisonous mushrooms? They are drugs, like other drugs and should be approached with the same caution.

This means, for example, that pregnant women should be as careful about medicinal herbs as they are about conventional medicines. Some medicinal herbs are clearly linked to birth defects. People on certain medications, like anti-coagulants or psychiatric drugs, can have serious problems from interactions between the herb and the medicine they're taking. In the US, herb labels do not list information about side effects, dangers and contraindications on the label (which I think they should). Many physicians are not well informed about herbs, and so you cannot always rely on your doctor to know about potential problems. And if you have or suspect you have a serious illness, it is very important to be under a doctor's care. Self diagnosis is not always accurate and self treatment doesn't always work.

I believe it is vital for any person who wishes to try herbs to be very well read before attempting them. I strongly recommend The Honest Herbal by Varro Tyler to anyone who is considering or using herbal medicines. It is the one herb book that I have ever found that relies solely on scientific studies instead of anecdotes and which provides references. Tyler himself has impressive credentials, being a tenured professor of pharmacognosy (the branch of pharmacy that deals with herbal medicine) in the school of pharmacy at Purdue University. The ISBN # is 1-56024-287-6 and it is published by the Haworth Press, 10 Alice Street, Binghamton NY 13904-1580. It is in print, costs about $20 and I got mine through a regular bookstore which special ordered it for me.

I personally regard herbal medicine as useful primarily in two situations: when a basically healthy person uses an herbal compound for a short, self limiting condition such as a cold or the flu, where over-the-counter remedies would normally be appropriate.

And in the case of serious illness, where no effective standard treatment exists and where there is some evidence from the scientific literature that a particular herbal compound may help.

An example of this would be the use of silymarin (an extract from milk thistle) in the treatment of chronic viral hepatitis. In this kind of situation, I regard it as extremely important that the person be under the close supervision of a physician well versed in the disease in question and who has reviewed the available studies on the herb to be used.

Herbal medicine has some very big problems. The most important is probably that herbs often have not been subjected to thorough testing. Even when an herb has many studies published about it, almost always the studies are on animals; human studies are quite unusual. Studies to determine whether the compound can cause birth defects are vanishingly rare, as are studies to determine whether the compound can cause cancer. Relying on traditional folklore is not much help; very obvious or dramatic adverse effects may be caught this way, but it doesn't tell us much about either long term effects or problems caused in only a small percentage of people.

Another major problem is that the amount of pharmacologically active ingredient available varies widely from plant to plant, so accurately regulating dosage is difficult. The pharmacologically active ingredient may also occur in conjunction with other toxic compounds. Examples of toxic agents often found in herbs include pyrrolizadine alkaloids (very toxic to the liver and cause both benign and malignant liver tumors); coumarins (which decrease the ability of the blood to clot); and allergens. The latter can be quite important to people who are allergic to ragweed; some herbs in the ragweed family (chamomile and yarrow are examples) can cause severe allergic reactions in these folks.) Most companies do not list the source of their herbs or how they were grown. Pesticide contamination is a possibility and heavy metal contamination of some herbs has been reported in the scientific literature.

Because of the problems mentioned above, I believe it is often better to rely on an extracted and standardized compound (conventional drugs) when possible. However, some of the active ingredients of herbs cannot be found in this form.

Yet another problem is with herb labeling. Very few herbal medicines marketed in the US have both the Latin name of the herb and an expiration date marked on the bottle. Often, this is deliberate: fraud is rampant among companies marketing herbs. One brand that does have good labeling is Nature's Way. Alternatively, if you live in a city with a large Chinese, Japanese or Korean population, you can try the herb sellers in that district. I've personally found the herb sellers in Chinatown here in L.A. to be very honest and knowledgeable (although language is often a problem, alas. Gotta learn to speak Chinese one of these days.)

If you decide, after your research, to try herbal medicines, you may wish to consult a trained herbalist. Unfortunately, in the US anyone can hang out a shingle and call themselves an herbalist. Lots of these people have no idea what they're doing. I have found practitioners of traditional Chinese medicine to be the best trained. I don't accept the model that traditional Chinese practitioners use to explain the effects of herbs (yin/yang, hot/cold, damp/dry, etc.). I also have problems with the amount of unsupported anecdotal info mixed in with scientific studies. But traditional Chinese doctors treat herbs with a lot of respect and caution. They are well up on the side effects and counter indications.

And finally, very few herb books contain dosage information. I have a lot of problems with Michael Tierra's herb books. I don't accept the medical models he endorses (traditional Chinese medicine and Ayurveda). I also don't like the fact that Tierra doesn't distinguish between scientifically validated information and folklore. But Tierra's books are among the very few herbal medicine books that discuss dosage. Just making up a weak tea is usually not enough to get a pharmacologically effective dose. Tierra is the author of The Way Of Herbs and Planetary Herbology.

Warning: Tierra's books should be used as supplemental sources only and never as your primary source of information on herbs. I have spotted several places where he has left out important information on toxicity.

Other references which may be of value:

A book which I have been told contains scientific references, but which I have not read myself, is the Encyclopedia of Natural Medicine by Michael Murray and Joseph Pizzorno. It's available from Prima Publishing, P.O. Box 1260MP, Rocklin, California 95677. The phone number is (916)786-0426 and the price is $18.95.

CRC Handbook of Medicinal Herbs, written by James A Duke, published 1985. Dr Duke was Chief of Medicinal Plant Resources Lab, USDA for 25 years. The book covers 365 medicinal plants, one for every day of the year. The "CRC" label on the cover ensures that the book will be thorough and exceedingly expensive to buy. There are nearly 700 large size pages.

A nice feature is having a sketch of each plant. At the back is a 7-page summary of each herb, toxicity score, scientific and common names, and estimated market price. The toxicity scores are given in triplets: Duke's own, Rose's, and Tyler's, (I don't know Rose's.) He admits that his scoring is ad hoc, all based on comparison with a cup of coffee! 3=safer than coffee and wouldn't hesitate to drink 3 cups a day. (He wouldn't drink anything more than 3 times a day.) 2=same as coffee, 2 cups. 1=more dangerous, would accept 1 cup a day containing 10 g of steeped herb. 0=very dangerous, wouldn't drink anything. He considers himself less conservative than Tyler, more conservative than Rose. The book, by the way, also has proper scientific citations.

This book is quite expensive, but may be available in some university libraries.

Herbal Remedies: Harmful and beneficial effects, by S Talalaj & A S Czechowicz. Publisher is Hill of Content Publishing Pty Ltd, 86 Bourke Street, Melbourne 3000, Australia. I don't have a fax number for them, nor a price, but from memory it cost only something like $20 in paperback form. They were happy to accept a VISA-card number.

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License