The traditional medical and folk uses and modern medicinal values of the plants described in this section are given for information only. Medicinal use of the plants mentioned should be carried out only under the care of a well-informed, qualified physician. Please note that some plants included in this booklet are poisonous and others may cause toxic reactions in susceptible individuals.
The unusual chemistry of pharmacologically useful plants is associated with unusual abilities to alter human metabolism. All substances that are medicinal can also be poisonous, and so the questions of safety and medicinal use are closely related.
In North America and elsewhere, there has been a growing popular movement toward the return of using herbs medicinally without the advice of doctors. Numerous "health food" or "natural food" stores and popular self-help books are fuelling this movement. As pointed out by Tyler (1984), much of popular herbal literature can only be classified as "advocacy literature," with almost every herb "good" for almost everything.
The problems of self-medication are manifold.
First is the question of medical competence: maintaining health and curing diseases of the human body are so obviously important that one wants the help of the best medical professionals, guided by thorough scientific knowledge.
Second, what works for the majority may not work for you, as humans vary greatly in their responses to plant constituents, and what may be harmless or even beneficial to most will harm others.
Third is the question of dosage. Natural (unrefined) plant materials and crude plant extracts and mixtures can vary widely in the concentration of active principles, and may be rather unpredictable in terms of interactions of the principles.
In pointing out the potential danger of personal use of plants for health purposes, we do not by any means suggest that the growing health food industry based on medicinal plants is an unwelcome development. We simply wish to emphasize that consumers and retailers need to be informed and cautious.
The following provides important guidelines for using and marketing medicinal herbs (also see WHO 1996 for additional advice on development and regulation, although not necessarily for Canada).
National Council Against Health Fraud Position Paper on Over-the Counter Herbal Remedies
The National Council Against Health Fraud (NCAHF) is an American non-profit health agency that focuses on health fraud, misinformation and quackery as public health problems. The following paragraphs are reproduced from NCAHF Newsletter Volume 18, Number 4 (July-August 1995), and provide an excellent set of guidelines for everyone concerned with herbal remedies (but keep in mind that this is written for the US).
The article may be reprinted provided appropriate credit is given to NCAHF. For a copy of the complete NCAHF Position Paper on OTC Herbal Remedies contact the NCAHF at P.O. Box 1276, Loma Linda, CA, 92354-1276, USA.
The over-the-counter (OTC) herbal remedies business is reported to be well over $1.5 billion in current sales with an estimated annual growth rate of 15%. In 1994, $813.8 million of the health food stores' $4.815 billion in sales (17%) were from herbal remedies.
Herbal product vendors benefit from society's romanticized view that equates "natural" with "safe." Unfortunately, the assumption that natural products are safe is false. It is precisely because herbs are a source of potent drugs that responsible people are concerned about the manner in which herbal remedies are being marketed.
Consumers are being denied the most fundamental information and assurances of quality. By law, drug labels must provide essential information, but herbal remedies are being marketed as "dietary supplements" with little of the type of information needed to enable people to use these remedies properly.
The herbal industry blames current regulatory policies for some of these problems. They say that FDA (Food and Drug Administration) regulations prevent them from supplying drug information because their products are regulated as dietary supplements. Herbal remedies cannot be profitably marketed if they have to meet the full requirements of drug approval.
Reformers argue for herbal remedies to be given special regulatory consideration. The FDA is bound by the law to regulate products that make medical claims as drugs. NCAHF finds the present situation untenable, but believes that there is room for regulatory adaptation without sacrificing consumer protection principles. Recommendations are directed at legislators and regulators, manufacturers and marketers, physicians, and consumers.
Recommendations to Legislators and Regulators
Establish a special category of OTC medicines called "Traditional Herbal Remedies" (THRs) regulated as follows:
- Labels must alert consumers to the fact that herbal remedies are held to a lower standard than that applied to standard medicines. Suggested wording: This product is regulated as a Traditional Herbal Remedy, a special category of medicines not required to meet the full stipulations of the US Food, Drug & Cosmetic Act applied to standard medicines.
- Limit THR products to those with properties sufficiently documented in the pharmacognosy literature to assure an acceptable measure of safety and efficacy.
- Limit herbal remedy products to those known not to have lethal or damaging side-effects when taken in overdose, or over an extended time period.
- Limit THRs to the treatment of non-serious, self-limiting ailments.
- Require THRs remedies to meet the same labelling standards for all drug products.
- Require plant sources to be identified by their scientific names.
- Require that all active ingredients (items that cause an effect) be quantitatively and qualitatively identified on the label.
- Require herbal remedy products to contain sufficient amounts of pharmacologically active substances for the product to perform as expected. Only those expectations that can be supported by science should be permitted on labels. The FDA should develop a set of acceptable claims just as it has done with health claims for foods.
- Require labels to inform consumers about what effects they should expect. Suggested wording: (e.g., valerian) The active ingredient in this product is valerian. Traditional folk medicinal uses for this substance include: as a sleep aid, and a relaxant. Valerian has been shown to depress the central nervous system at the doses indicated.
- Require a highly visible, easily accessible post-marketing surveillance system for tracking unanticipated adverse reactions. The system must enable consumers as well as health professionals to report, and regulators to gather and disseminate information on adverse effects. A good candidate for the agency to receive reports is the US Pharmacopeia Practitioner Reporting System which passes reports on to the FDA and Poison Control Centers. Suggested wording: Adverse reactions associated with the use of this product should be reported to 1-800-638-6725.
- Require manufacturers to mark product batches for identification, testing, and tracking.
- Require warnings about dangers of self-treatment on labels and (or) package inserts. Suggested wording: Caution: Self-treatment may delay proper health care. See a medical doctor if health problems persist.
- Require substantial representation from outside of the herbal industry to assure sufficient scepticism in herbal regulation.
- Impose strong penalties for adulterating herbal products with potentially dangerous substances.
Recommendations to Herbal Remedy Product Manufacturers and Marketers
NCAHF believes that herbal remedy producers would be wise to take a long range approach to marketing. Just as compliance with food and drug regulations has enabled the American pharmaceutical industry to establish itself as the standard of quality, by adopting high standards, herbal marketers will assure themselves a superior competitive position and longevity.
- Adopt the most scientific standards as are practical in your manufacturing and promotions, including the rejection of pseudoscientific herbal products such as homeopathic concoctions.
- Conduct ongoing consumer education warning consumers that: Information found in traditional herbal books is not necessarily reliable as a guide to self-treatment.
The designations "herbologist," "herbalist," "Master Herbalist," and similar terms, have no legal or scientific meaning, and may be indicative of quackery. Likewise, sources issuing credentials in "herbology," "herbalism," and the like, are usually "diploma mills."
Recommendations to Physicians
- Routinely ask patients about their use of herbal products.
- Report adverse effects utilizing either the US Pharmacopeia Practitioner Reporting System or FDA's MedWatch Form 3500, or fax to 1-800-FDA-0178.
- Write up and submit for publication case reports in which patients have experienced adverse effects from herbal product use. Include information on how the patient learned of the product and how its use was discovered.
Physicians may obtain information on herbal drugs and drug interactions from Registered Pharmacists at hospital pharmacies or from Poison Control Centers. Information on some herbal drugs, interactions, or synergistic effects may be obscure or unavailable. These are among the additional risks that those who choose to use medicinal herbal products currently face.
Recommendations to Consumers
- Do not assume that herbal remedies are safe simply because they are natural. Herbal remedies contain substances that can have powerful effects upon the mind and (or) body. Use even greater cautions than when taking standard medications.
- Be cautious about taking medicinal herbs if you are pregnant or attempting to become pregnant.
- Be cautious about taking medicinal herbs if you are breast feeding a baby; herbal drugs in the body may be transferred to breast milk.
- Do not give herbs to infants or children.
- Do not take large quantities of any herbal preparation.
- Do not take any medicinal herb on a prolonged daily basis.
- Buy only preparations that identify plants on the label and state contraindications for use.
- Become familiar with the names of potentially dangerous herbs and be cautious about their use.
- If you are taking medications, do not use medicinal herbs without checking with your doctor.
- Do not trust your health to unqualified practitioners who use unregulated titles such as "herbalist," "herb doctor," "Master Herbalist," "herbologist," "Natural Health Counsellor," or the like.
- Beware of exaggerated claims for the benefits of herbal remedies.
- Insist that herbal marketers meet basic consumer protection standards of labelling, safety and efficacy.
For an extensive World wide Web site dealing with the toxic potential of medicinal plants, see Adverse Effects of Herbs. For perspective, it may be noted that adverse drug reactions from pharmaceutical drugs alone represent a very significant health hazard, far exceeding the danger posed by medicinal plants (although pharmaceuticals are generally employed to treat more serious conditions than are herbals).
In the US, some estimates hold that over 1% of patients suffer adverse drug reactions from pharmaceuticals, costing thousands of dollars on average, and perhaps associated with over 100,000 fatalities annually; see the Journal of the American Medical Association (JAMA), which regularly has articles and letters treating this subject.
The American Herbal Products Association's botanical safety handbook (McGuffin et al. 1997) provides safety data and labelling recommendations for over 600 commonly sold herbal products (for the US). Authoritative guidelines for the safe use of herbs as medicines are provided by the German Federal Health Agency's "Commission E" which has produced more than 300 detailed herbal monographs.
Herbal remedies and Canadian law
Anyone contemplating growing, manufacturing, or selling medicinal herbs in Canada must be acquainted with Health Canada's regulations. These regulations have changed recently, and in response to considerable public and private sector concerns, may undergo additional changes or refinement.
The Canadian Food and Drug Act provides for the sanitary manufacture of food and drugs, the prohibition of sale of harmful foods and drugs, and the accurate labelling and advertising of foods and drugs.
Products can be classified as foods or drugs depending on their purpose. Garlic, for example, is mostly sold as a condiment (i.e., as food), but is also commonly promoted as a drug capable of lowering cholesterol and having other properties beneficial to health. Herbal products can therefore, at least in theory, be marketed either as food or as drugs. Herbal drugs, however, may also be considered as a special category, as noted below.
"Traditional herbal remedies" (THMs) are defined as "finished drug products intended for self-medication that contain, as the active principles, herbal ingredients that have received relatively little attention in world scientific literature, but for which traditional or folkloric use is well-documented in herbal references."
Commercial drugs may not be present in THMs. THMs can be marketed in Canada as over-the-counter drugs intended to treat given ailments, if certain conditions are met, such as scientific proof of efficacy, standardization of dosage, a statement of contraindications, and proof of adherence to acceptable manufacturing and quality standards.
Examples of herbal remedies discussed in this work include: dandelion for use as a diuretic, cascara as a laxative, and hop as a sedative. To qualify as a THM, the herbal remedy must be intended to treat only a minor ailment (one that if untreated would not usually have serious consequences), and the symptoms and the success of the treatment should be easily diagnosable by the user.
A number of ailments are listed in the Food and Drugs Act that are considered too serious to be treated by THMs (such as alcoholism, appendicitis, arthritis, asthma, cancer, diabetes, epilepsy, glaucoma, menstrual flow disorder, and prostate disease).
Some THMs are approved with restrictions; for example, arnica may only be used externally. There are various general restrictions, for example limitation of THM products to those over 11 years of age, and on the circumstances when specific dosages can be recommended to pregnant or breastfeeding women. Homeopathic use of herbs is governed by separate regulations (homeopathy in its narrow sense treats illness by applying highly diluted doses of alleged remedies that in higher concentrations produce symptoms of the disease treated; see Homeopathy.
Herbal drugs whose safety and efficacy are well accepted scientifically are not considered to be THMs. Some of these may already be accepted and registered as drugs (such as May-apple), but if not, they can be registered under the New Drug Submission procedures.
Registration consists of issuing a Drug Identification Number (DIN) or General Product (GP) Number upon approval, for either a traditional herbal medicine or a New Drug Submission; approvals for THMs cost less than a thousand dollars, while approvals for new drugs cost more than $100,000 (the fee for evaluation of supporting data).
Information to produce and register a THM is available from: Health Canada Drug Directorate, Tunney's Pasture, Address Locator #0702A, Ottawa, ON, K1A OL2.
Another useful discussion (although not sympathetic to the use of herbs as medicines) is Kozyrskyj (1997). Appendix H in Holm and MacGregor (1998) has reprints of the following very useful documents:
- "Draft regulatory framework for natural health products (Interim report of the Advisory Panel on Natural Health Products, Presentation to the House of Commons Standing Comittee on Health, Feb. 3, 1998)";
- "Good manufacturing practices (Supplementary guidelines for the manufacture of herbal medicinal products, final version, October 1996, Health Canada)";
- "Good manufacturing practices (Supplementary guidelines for homeopathic preparations, final version, October 1996, Health Canada";
- "Drugs Directorate Guideline, traditional herbal medicines, revised October 1995)."
Many natural health products are regulated as foods, because they do not make medical claims, although they may in fact either be sold or bought for therapeutic purposes. The regulation of these is a matter of current dispute, with some in the health product industry concerned about the possibility of excessively restrictive regulations limiting consumer choice; on the other hand, there are those who are concerned about the consumer being misled or exposed to harmful substances as a result of insufficiently restrictive regulations.
Most herbal products sold as foods are found in health food stores and pharmacies, and are often listed as "dietary aids" or with labelling indicating in a general way purported benefits. Unqualified personnel (i.e., without formal academic and licensing requirements) sometimes promote the use of given herbal products to treat disease, although such promotion is illegal in Canada.
Moreover, it is clear that many consumers are attempting self-medication for conditions that require professional care. The debate extends to some herbal products that are currently restricted, some believing that the comparatively much less restrictive environment in European nations is desirable.
Health Canada's "Advisory Panel on Natural Health Products" is currently evaluating these issues. An excellent examination of the situation is: Hearings on the regulation of natural products in Canada: determining the appropriate regulatory framework for herbal remedies. A brief presented to the Standing Committee on Health, March 12, 1998, by A.R. McCutcheon and D. Awang, representing the Canadian Herb Society. Herbal Times (Canadian Herb Society Journal).
Some herbal medicines are being sold without the approval of Health Canada, and could be hazardous. Serious liver and kidney disease, and some types of cancer are known to have been caused by certain herbs. Some illegally imported medications from Asia have been found to contain dangerous levels of heavy metals such as arsenic and mercury. Several illegal herbal preparations have been found to be adulterated with prescription drugs such as benzodiazepines, steroids, hormones, diuretics and anti-inflammatories.
An eight digit Drug Identification Number or General Product Number signifies that the product has been approved for sale in Canada. Adverse reactions should be reported (to your doctor, pharmacist, and (or) directly to Health Canada), in order to promote the safer use of herbals.
Herbal remedies and American law
From a Canadian perspective, it is important to appreciate the regulatory and legal framework of medicinal herbs in the US because:
- this is Canada's largest export market
- the US has a major influence on public opinion in Canada, hence on Canadian regulation of herbals.
The Dietary Supplement Health and Education Act passed in 1994 is the essential legislation governing herbal products. This act allows for the marketing of many herbals as dietary supplement ingredients without FDA approval, provided that the manufacturer states that the ingredients have a history of dietary use and have not been sold in the US as drugs.
The category "dietary supplements" was created to distinguish such substances from either "foods" (consumed to support the body's structure and function) or "drugs" (designed to treat disease). Dietary supplements include vitamins, minerals, and amino acids, in addition to herbs. Labels for dietary supplements can list the part or function of the body affected, but therapeutic claims are not permitted (unless the statements are backed by clinical research, or "if such claims are based on current, published, authoritative statements from certain federal scientific bodies, as well as from the National Academy of Sciences".
The Internet as a source of medical misinformation
"Science and snake oil may not always look all that different on the Net."
Silberg et al. (cited below)
This article The Internet as a source for current patient information is particularly important as a warning to those who use the Internet to obtain medicinal information, and hence to those concerned with herbal information currently on the Web: [Juhling McClung, H., Murray, R.D., and Heitlinger, L.A. 1998. The Internet as a source for current patient information. Pediatrics 101(6): p. e2].
Based on the treatment of childhood diarrhea, these authors surveyed Internet articles, and found a low concurrence with recommended treatment. They concluded that: "Patients must be warned about the voluminous misinformation available on medical subjects on the Net," and "Practitioners need to warn their patients about the need for a very critical review of all medical information obtained from the Web, even when it seems to be from a 'reliable' source."
Another excellent review (with links to related articles) is: Silberg, W.M., Lundberg, G.D., and Musacchio, R.A. 1997. Assessing, controlling, and assuring the quality of medical information on the Internet. Journal of the American Medical Association 277:1244-1245