Herbal supplements are a type of dietary supplement that contains herbs, either singly or in mixtures. An herb (also called a botanical) is a plant or plant part used for its scent, flavor, and/or therapeutic properties.
Many herbs have a long history of use and of claimed health benefits. However, some herbs have caused health problems for users. This fact sheet contains points you should consider for your safety if you use, or are thinking about using, herbs for health purposes. It does not discuss whether herbs work for specific diseases and conditions. To find out more about topics and resources mentioned in this fact sheet, see "For More Information".
- It's important to know that just because an herbal supplement is labeled "natural" does not mean it is safe or without any harmful effects. For example, the herbs kava and comfrey have been linked to serious liver damage.
- Herbal supplements can act in the same way as drugs. Therefore, they can cause medical problems if not used correctly or if taken in large amounts. In some cases, people have experienced negative effects even though they followed the instructions on a supplement label.
- Women who are pregnant or nursing should be especially cautious about using herbal supplements, since these products can act like drugs. This caution also applies to treating children with herbal supplements.
- It is important to consult your health care provider before using an herbal supplement, especially if you are taking any medications (whether prescription or over-the-counter). Some herbal supplements are known to interact with medications in ways that cause health problems. Even if your provider does not know about a particular supplement, he can access the latest medical guidance on its uses, risks, and interactions.
- If you use herbal supplements, it is best to do so under the guidance of a medical professional who has been properly trained in herbal medicine. This is especially important for herbs that are part of a whole medical system, such as traditional Chinese medicine or Ayurvedic medicine.
- In the United States, herbal and other dietary supplements are regulated by the U.S. Food and Drug Administration (FDA) as foods. This means that they do not have to meet the same standards as drugs and over-the-counter medications for proof of safety, effectiveness, and what the FDA calls Good Manufacturing Practices.
About Dietary Supplements
Dietary supplements were defined in a law passed by Congress in 1994. A dietary supplement must meet all of the following conditions:
- It is a product (other than tobacco) intended to supplement the diet, which contains one or more of the following: vitamins; minerals; herbs or other botanicals; amino acids; or any combination of the above ingredients.
- It is intended to be taken in tablet, capsule, powder, softgel, gelcap, or liquid form.
- It is not represented for use as a conventional food or as a sole item of a meal or the diet.
- It is labeled as being a dietary supplement.
- The active ingredient(s) in many herbs and herbal supplements are not known. There may be dozens, even hundreds, of such compounds in an herbal supplement. Scientists are currently working to identify these ingredients and analyze products, using sophisticated technology. Identifying the active ingredients in herbs and understanding how herbs affect the body are important research areas for the National Center for Complementary and Alternative Medicine (NCCAM).
- Published analyses of herbal supplements have found differences between what's listed on the label and what's in the bottle. This means that you may be taking less--or more--of the supplement than what the label indicates. Also, the word "standardized" on a product label is no guarantee of higher product quality, since in the United States there is no legal definition of "standardized" (or "certified" or "verified") for supplements.
- Some herbal supplements have been found to be contaminated with metals, unlabeled prescription drugs, microorganisms, or other substances.
- There has been an increase in the number of Web sites that sell and promote herbal supplements on the Internet. The Federal Government has taken legal action against a number of company sites because they have been shown to contain incorrect statements and to be deceptive to consumers. It is important to know how to evaluate the claims that are made for supplements. Some sources are listed below.
For More Information
The NCCAM Clearinghouse provides information on complementary and alternative medicine (CAM) and NCCAM, including publications and searches of Federal databases of scientific and medical literature. Examples of publications include "Are You Considering Using CAM?" and "10 Things To Know About Evaluating Medical Resources on the Web." The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.
Toll-free in the U.S.: 1-888-644-6226
TTY (for deaf and hard-of-hearing callers): 1-866-464-3615
Web site: nccam.nih.gov
U.S. Food and Drug Administration (FDA)
The FDA oversees the safety of many products, such as foods (including dietary supplements), medicines, medical devices, and cosmetics.
Web site: fda.gov
Toll-free in the U.S.: 1-888-463-6332
Office of Dietary Supplements (ODS), NIH
ODS seeks to strengthen knowledge and understanding of dietary supplements by evaluating scientific information, supporting research, sharing research results, and educating the public. Its resources include publications and the International Bibliographic Information on Dietary Supplements (IBIDS) database.
Web site: ods.od.nih.gov
CAM on PubMed®
A service of the National Library of Medicine (NLM), PubMed contains publication information and (in most cases) brief summaries of articles from scientific and medical journals. CAM on PubMed, developed jointly by NCCAM and NLM, is a subset of the PubMed system and focuses on the topic of CAM.
Web site: ncbi.nlm.nih.gov/entrez/
CAM on PubMed: nccam.nih.gov/camonpubmed/
The Cochrane Database of Systematic Reviews
The Cochrane Database of Systematic Reviews is a collection of evidence-based reviews produced by the Cochrane Library, an international nonprofit organization. The reviews summarize the results of clinical trials on health care interventions. Summaries are free; full-text reviews are by subscription only.
Web site: www.cochrane.org/reviews/