Along with massage therapy, herbal treatment is undoubtedly one of the most ancient forms of medicine. By the time written history began, herbal medicine was already in full swing and being used in all parts of the world.
There are several major surviving schools of herbal medicine. Two of the most complex systems are Ayurveda (the traditional herbal medicine of India) and Traditional Chinese Herbal Medicine (TCHM). Both Ayurveda and TCHM make use of combinations of herbs. However, the herbal tradition in the West focuses more on individual herbs, sometimes known as simples. That is the form of herbology discussed here.
Originally, herbal medicine in Europe was primarily a women’s art. The classic image of witches boiling herbs in a cauldron stems to a large extent from this period. Beginning in about the 13th century, however, graduates of male-only medical schools and members of barber-surgeon guilds began to displace the traditional female village herbalists. Ultimately, much of the original lore was lost. (So-called traditional herbal compendiums, such as Culpeppers Herbal, are actually of fairly recent vintage.)
Another major change took place in the 19th century, when chemistry had advanced far enough to allow extraction of active ingredients from herbs. The old French word for herb, “drogue,” became the name for chemical “drugs.” Subsequently, these chemical extracts displaced herbs as the standard of care. There were several forces leading to the predominance of chemicals over herbs, but one of the most important remains a major issue today: the problem of reproducibility.
When you purchase a drug, you generally know exactly what you are getting. Drugs are single chemicals that can be measured and quantified down to their molecular structure. Thus a tablet of extra-strength Tylenol contains 500 mg of acetaminophen, no matter where or when you buy it. Although a vitamin, not a drug, the same is true of a vitamin C tablet, provided that it is correctly labeled.
Herbs, however, are living organisms comprised of thousands of ingredients, and the proportions of all these ingredients may differ dramatically between two plants. Numerous influences can affect the nature of a given crop. Whether it was grown at the top or bottom of a hill, what the weather was like, what time of year it was picked, what other plants lived nearby, and what kind of soil predominated are only a few of the factors that can affect an herb’s chemical makeup.1
This presents a real problem for people who wish to use herbs medicinally (as opposed to, say, for taste or fragrance). Since so much variation is possible, it’s difficult to know whether one batch of an herb is equivalent in effectiveness to another.
The desire to overcome this problem provided the main initial motivation for finding the active principles of herbs and purifying them into single-chemical drugs. However, by now most of the common herbs that possess an identifiable active ingredient have long since been turned into drugs. Today’s popular herbs do not contain any known, single active ingredients. For this reason, there’s no simple way to determine the effectiveness of a given herbal batch.
This difficulty can be partially overcome by a method called “herbal standardization.” 2 In this process, manufacturers make an extract of the whole herb and boil off the liquid until the concentration of some ingredient reaches a certain percentage. Contrary to popular belief, this ingredient is not usually the active ingredient; it is merely a “tag” or “handle” used for standardization purposes.
The extract is then made into tablets or capsules or bottled as a liquid, with the concentration of the tag ingredient listed on the label. This method is far from perfect because two products with the same concentration of tag ingredients may still differ widely in other unlisted or even unidentified active constituents. Nonetheless, this form of partial standardization is better than nothing, and it allows a certain amount of reproducibility. For this reason, we recommend that whenever possible, you should use standardized herbal extracts. Even better, use the actual products that were tested in double-blind studies.
There is no doubt that herbs can be effective treatments in principle, if for no other reason than that up through perhaps the 1970s, most drugs used in medicine came from herbs. Many of today’s medicinal herbs have been studied in meaningful double-blind, placebo-controlled trials that provide a rational basis for believing them effective. Some of the best substantiated include ginkgo for Alzheimer’s disease, St. John’s wort for mild to moderate depression, and saw palmetto for benign prostatic hypertrophy.
However, even the best-documented herbs have less supporting evidence than the majority of drugs for one simple reason: You can’t patent an herb; therefore, no single company has the financial incentive to invest millions of dollars in research when another company can “steal” the product after it is proved to work. In addition, the problem of reproducibility always makes it difficult or impossible to know whether the batch of herbs you are buying is as effective as the one tested in published studies.
Each herb entry in this database analyzes the body of scientific evidence for its effectiveness. We also note the traditional uses of each herb, but keep in mind that such uses are not reliable indicators of an herb’s effectiveness. For many reasons, it simply isn’t possible to accurately evaluate the effectiveness of a medical treatment without performing double-blind, placebo-controlled studies, and many herbs lack these. (For more information on why this is so, see Why Does This Database Rely on Double-blind Studies?)
There is a common belief that herbs are by nature safer and gentler than drugs. However, there is no rational justification for this belief; an herb is simply a plant that contains one or more drugs, and it is just as prone to side effects as any medicine, especially when taken in doses high enough to cause significant benefits.
Nonetheless, the majority of the most popular medicinal herbs are at least fairly safe. The biggest concern in practice tends to involve interactions with medications. Many herbs are known to interact with drugs, and as research into this area expands, more such interactions will certainly be discovered. Each herb entry in this database lists what is known about all safety risks. See also the article on which herbs and supplements to avoid in pregnancy.
This database has articles on all major herbal therapies. For detailed information, see the herb and supplement index page.
1. Bratman S, Girman A. Mosby’s Handbook of Herbs and Supplements and their Therapeutic Uses. St. Louis, MO:Mosby, Inc.; 2003.
2. Schulz V, Hansel R, Tyler V. Rational Phytotherapy. A Physician’s Guide to Herbal Medicine. Berlin and Heidelberg:Springer-Verlag; 1998.
Last reviewed December 2015 by EBSCO CAM Review Board
Last Updated: 12/15/2015