Peppermint is a flavor many people enjoy, whether as a candy or perhaps in tea. Garlic adds a spicy bite to many favorite dishes. But you may not realize, as you sip your peppermint tea or chop raw garlic into your pesto, that you are eating herbs with medicinal properties. And like conventional medications, medicinal herbs can interact -- with each other and with prescribed or over-the-counter medicines.
What is Herbalism?
Herbalism, also called phytomedicine, herbal medicine or botanical medicine, has a long tradition in many cultures. The ancient Chinese and Egyptians wrote extensively on the use of plants as medicine, and at one time these were the only resource for medical treatment. It was not until the early 19th century that the science of chemistry allowed what we commonly call medicines to be developed, first by extracting the desired compound from plants, and later by chemical synthesis. The practice of herbalism faded under the more widespread use of chemically synthesized drugs but has recently risen in interest.
About Herbal Supplements
Herbal supplements are considered food supplements by the Food and Drug Administration, so their manufacture and sale are essentially unregulated. Herbs are readily available in health food stores, drug stores and even supermarkets, and no prescription is necessary to buy them. According to the University of Maryland Medical Center, these are the most commonly used herbal supplements in the United States: echinacea (Echinacea purpurea and related species), ginseng (Panax ginseng, or Asian ginseng; and Panax quinquefolius, or American ginseng), goldenseal (Hydrastis canadensis), St. John's wort (Hypericum perforatum), chamomile (Matricaria recutita), feverfew (Tanacetum parthenium), ginkgo (Ginkgo biloba), garlic (Allium sativum), saw palmetto (Serenoa repens), valerian (Valeriana officinalis), ginger (Zingiber officinale), evening primrose (Oenothera biennis) and milk thistle (Silybum marianum).
Examples of Herb-Drug Interactions
Herbal medications can have a variety of effects in the human body, just like conventional drugs, yet many people seem to think that because the herbs are "natural" they are safe to use. In some cases that may be true -- but in others it's not. For example, ginkgo, one of the herbs on the list above, is used in herbalism to treat circulatory disorders because it reduces the stickiness of blood platelets. But that means it may interact with some blood thinning medicines or even aspirin, which has a similar effect. St. John's wort, another commonly used supplement -- in this case for depression -- interacts with a number of medications, among them birth control pills. And it can also interfere with blood thinners such as warfarin. Garlic, the UMMC reports, can increase the risk of bleeding. And even peppermint can cause heartburn, allergic reactions and headache; peppermint oil, according to Medline Plus, can affect how the liver handles a variety of prescription medications.
Considerations and Warnings
No matter how innocuous you think an herbal tea or supplement is, you should always remember the potential for medication interactions. There are a number of resources available for you to research possible side effects and medication interactions, such as The University of Michigan's "Selected Herb-Drug Interactions" or the U.S. National Library of Medicine's "Drugs, Supplements and Herbal Information," available on Medline Plus (see Resources). None of these should substitute for a discussion with your health care professional, so be sure to keep her in the communication loop if you decide to use herbal medicines.
References
- University of Maryland; Herbal Medicine; Steven D. Ehrlich, NMD; September 2009
- National Library of Medicine; Medlineplus Drug Information; Peppermint; November 2010
- National Library of Medicine; Medlineplus Drug Information; Garlic; December 2010
- University of Michigan; Health Topics; Selected Herb-Drug Interactions
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