What is herbal medicine?
Herbal medicine, also called botanical medicine or phytomedicine, refers to using a plant's seeds, berries, roots, leaves, bark, or flowers for medicinal purposes. Herbalism has a long tradition of use outside conventional medicine. It is becoming more mainstream as improvements in analysis and quality control, along with advances in clinical research, show the value of herbal medicine in treating and preventing disease.
What is the history of herbal medicine?
Plants have been used for medicinal purposes long before recorded history. Ancient Chinese and Egyptian papyrus writings describe medicinal uses for plants as early as 3,000 BC. Indigenous cultures (such as African and Native American) used herbs in their healing rituals, while others developed traditional medical systems (such as Ayurveda and Traditional Chinese Medicine) in which herbal therapies were used. Researchers found that people in different parts of the world tended to use the same or similar plants for the same purposes.
In the early 19th century, when chemical analysis first became available, scientists began to extract and modify the active ingredients from plants. Later, chemists began making their own version of plant compounds and, over time, the use of herbal medicines declined in favor of drugs. Almost one fourth of pharmaceutical drugs are derived from botanicals.
Recently, the World Health Organization estimated that 80% of people worldwide rely on herbal medicines for some part of their primary health care. In Germany, about 600 to 700 plant based medicines are available and are prescribed by some 70% of German physicians. In the past 20 years in the United States, public dissatisfaction with the cost of prescription medications, combined with an interest in returning to natural or organic remedies, has led to an increase in herbal medicine use.
How do herbs work?
In many cases, scientists are not sure what specific ingredient in a particular herb works to treat a condition or illness. Whole herbs contain many ingredients, and they may work together to produce a beneficial effect. Many factors determine how effective an herb will be. For example, the type of environment (climate, bugs, and soil quality) in which a plant grew will affect it, as will how and when it was harvested and processed.
How are herbs used?
The use of herbal supplements has increased dramatically over the past 30 years. Herbal supplements are classified as dietary supplements by the U.S. Dietary Supplement Health and Education Act (DSHEA) of 1994. That means herbal supplements, unlike prescription drugs, can be sold without being tested to prove they are safe and effective. However, herbal supplements must be made according to good manufacturing practices.
The most commonly used herbal supplements in the U.S. include:
- Echinacea (Echinacea purpurea and related species)
- St. John's wort (Hypericum perforatum)
- Ginkgo (Ginkgo biloba)
- Garlic (Allium sativum)
- Saw palmetto (Serenoa repens)
- Ginseng (Panax ginseng or Asian ginseng) and Panax quinquefolius or American ginseng)
- Goldenseal (Hydrastis canadensis)
- Valerian (Valeriana officinalis)
- Chamomile (Matricaria recutita)
- Feverfew (Tanacetum parthenium)
- Ginger (Zingiber officinale)
- Evening primrose (Oenothera biennis)
- Milk thistle (Silybum marianum)
Practitioners often use herbs together because the combination is more effective. Health care providers must take many factors into account when recommending herbs, including the species and variety of the plant, the plant's habitat, how it was stored and processed, and whether or not there are contaminants (including heavy metals and pesticides).
What is herbal medicine good for?
Herbal medicine is used to treat many conditions, such as allergies, asthma, eczema, premenstrual syndrome, rheumatoid arthritis, fibromyalgia, migraine, menopausal symptoms, chronic fatigue, irritable bowel syndrome, and cancer, among others. It is best to take herbal supplements under the guidance of a trained provider. For example, one study found that 90% of people with arthritic use alternative therapies, such as herbal medicine. Since herbal medicines can potentially interact with prescription medications, and may worsen certain medical conditions, be sure to consult with your doctor or pharmacist before taking any herbs. Some common herbs and their uses are discussed below.
- Ginkgo (Ginkgo biloba) has been used in traditional medicine to treat circulatory disorders and enhance memory. Although not all studies agree, ginkgo may be especially effective in treating dementia (including Alzheimer disease) and intermittent claudication (poor circulation in the legs). It also shows promise for enhancing memory in older adults. Laboratory studies have shown that ginkgo improves blood circulation by dilating blood vessels and reducing the stickiness of blood platelets. By the same token, this means ginkgo may also increase the effect of some blood-thinning medications, including aspirin. People taking blood-thinning medications should ask their doctor before using ginkgo. People with a history of seizures and people with fertility issues should also use concern; Speak with your physician.
- Kava kava (Piper methysticum) is said to elevate mood, enhance wellbeing and contentment, and produce a feeling of relaxation. Several studies show that kava may help treat anxiety, insomnia, and related nervous disorders. However, there is serious concern that kava may cause liver damage. It is not clear whether the kava itself caused liver damage in a few people, or whether it was taking kava in combination with other drugs or herbs. It is also not clear whether kava is dangerous at previously recommended doses, or only at higher doses. Some countries have taken kava off the market. It remains available in the United States, but the Food and Drug Administration (FDA) issued a consumer advisory in March of 2002 regarding the "rare" but potential risk of liver failure associated with kava-containing products.
- Saw palmetto (Serenoa repens) is used by more than 2 million men in the United States for the treatment of benign prostatic hyperplasia (BPH), a noncancerous enlargement of the prostate gland. Several studies suggest that the herb is effective for treating symptoms, including frequent urination, having trouble starting or maintaining urination, and needing to urinate during the night. But not all studies agree. At least one well-conducted study found that saw palmetto was no better than placebo in relieving the signs and symptoms of BPH.
- St. John's wort (Hypericum perforatum) is well known for its antidepressant effects. In general, most studies have shown that St. John's wort may be an effective treatment for mild-to-moderate depression, and has fewer side effects than most other prescription antidepressants. But the herb interacts with a wide variety of medications, including birth control pills, and can potentially cause unwanted side effects, so it is important to take it only under the guidance of a health care provider.
- Valerian (Valeriana officinalis) is a popular alternative to commonly prescribed medications for sleep problems because it is considered to be both safe and gentle. Some studies bear this out, although not all have found valerian to be effective. Unlike many prescription sleeping pills, valerian may have fewer side effects, such as morning drowsiness. However, Valerian does interact with some medications, particularly psychiatric medications, so you should speak to your doctor to see if Valerian is right for you.
- Echinacea preparations (from Echinacea purpurea and other Echinacea species) may improve the body's natural immunity. Echinacea is one of the most commonly used herbal products, but studies are mixed as to whether it can help prevent or treat colds. A review of 14 clinical studies examining the effect of echinacea on the incidence and duration of the common cold found that echinacea supplements decreased the odds of getting a cold by 58%. It also shortened the duration of a cold by 1.4 days. Echinacea can interact with certain medications and may not be right for people with certain conditions, for example people with autoimmune disorders or certain allergies. Speak with your physician.
Buying standardized herbal supplements helps ensure you will get the right dose and the effects similar to human clinical trials. Ask your doctor or pharmacist about which herbal supplements are best for your health concerns.
Is there anything I should watch out for?
Used correctly, herbs can help treat a variety of conditions, and in some cases, may have fewer side effects than some conventional medications. Never assume that because herbs are "natural," they are safe. Some herbs may be inappropriate for people with certain medical conditions. Because they are unregulated, herbal products are often mislabeled and may contain additives and contaminants that are not listed on the label. Some herbs may cause allergic reactions or interact with conventional drugs, and some are toxic if used improperly or at high doses. Taking herbs on your own increases your risk, so it is important to consult with your doctor or pharmacist before taking herbal medicines. Some examples of adverse reactions from certain popular herbs are described below.
- St. John's wort can cause your skin to be more sensitive to the sun's ultraviolet rays, and may cause an allergic reaction, stomach upset, fatigue, and restlessness. Clinical studies have found that St. John's wort also interferes with the effectiveness of many drugs, including the blood thinner warfarin (Couamdin), protease inhibitors for HIV, birth control pills, certain asthma drugs, and many other medications. In addition, St. John's wort should not be taken with prescribed antidepressant medication. The FDA has issued a public health advisory concerning many of these interactions.
- Kava kava has been linked to liver toxicity. Kava has been taken off the market in several countries because of liver toxicity.
- Valerian may cause sleepiness, and in some people it may even have the unexpected effect of overstimulating instead of sedating.
- Garlic, ginkgo, feverfew, and ginger, among other herbs, may increase the risk of bleeding.
- Evening primrose (Oenothera biennis) may increase the risk of seizures in people who have seizure disorders and bleeding in people with bleeding disorders or who take blood-thinning medications, such as warfarin (Coumadin).
Some herbal supplements, especially those imported from Asian countries, may contain high levels of heavy metals, including lead, mercury, and cadmium. It is important to purchase herbal supplements from reputable manufacturers to ensure quality. Many herbs can interact with prescription medications and cause unwanted or dangerous reactions. For example, there is a high degree of herb/drug interaction among patients who are under treatment for cancer. Be sure to consult your doctor before trying any herbal products.
Who is using herbal medicine?
Nearly one-third of Americans use herbs. Unfortunately, a study in the New England Journal of Medicine found that nearly 70% of people taking herbal medicines (most of whom were well educated and had a higher-than-average income) were reluctant tell their doctors that they used complementary and alternative medicine (CAM).
How is herbal medicine sold in stores?
The herbs available in most stores come in several different forms: teas, syrups, oils, liquid extracts, tinctures, and dry extracts (pills or capsules). You can make teas from dried herbs left to soak for a few minutes in hot water, or by boiling herbs in water and then straining the liquid. Syrups, made from concentrated extracts and added to sweet-tasting preparations, are often used for sore throats and coughs. Oils are extracted from plants and often used as rubs for massage, either by themselves or as part of an ointment or cream. Tinctures and liquid extracts are made of active herbal ingredients dissolved in a liquid (usually water, alcohol, or glycerol). Tinctures are typically a 1:5 or 1:10 concentration, meaning that one part of the herb is prepared with 5 to 10 parts (by weight) of the liquid. Liquid extracts are more concentrated than tinctures and are typically a 1:1 concentration. A dry extract form is the most concentrated form of an herbal product (typically 2:1 to 8:1) and is sold as a tablet, capsule, or lozenge.
No organization or agency regulates the manufacture or certifies the labeling of herbal preparations. This means you cannot be sure that the amount of the herb contained in the bottle, or even from dose to dose, is the same as what is stated on the label. Some herbal preparations are standardized, meaning that the preparation is guaranteed to contain a specific amount of the active ingredients of the herb. However, it is still important to ask companies making standardized herbal products about their product's guarantee. It is important to talk to your doctor or an expert in herbal medicine about the recommended doses of any herbal products.
Are there experts in herbal medicine?
Herbalists, chiropractors, naturopathic physicians, pharmacists, medical doctors, and practitioners of Traditional Chinese Medicine all may use herbs to treat illness. Naturopathic physicians believe that the body is continually striving for balance and that natural therapies can support this process. They are trained in 4-year, postgraduate institutions that combine courses in conventional medical science (such as pathology, microbiology, pharmacology, and surgery) with clinical training in herbal medicine, homeopathy, nutrition, and lifestyle counseling.
How can I find a qualified herbalist in my area?
For additional information, or to locate an experienced herbalist in your area, contact the American Herbalists Guild (AHG) site at
What is the future of herbal medicine?
In some countries in Europe, unlike the U.S., herbs are classified as drugs and are regulated. The German Commission E, an expert medical panel, actively researches their safety and effectiveness.
While still not widely accepted, herbal medicine is being taught more in medical schools and pharmacy schools. More health care providers are learning about the positive and potentially negative effects of using herbal medicines to help treat health conditions. Some health care providers, including doctors and pharmacists, are trained in herbal medicine. They can help people create treatment plans that use herbs, conventional medications, and lifestyle changes to promote health.
Abeloff. Abeloff: Abeloff's Clinical Oncology. 4th ed. Philadelphia, PA: Elsevier Churchill Livingstone; 2008.
Altschuler JA, Casella SJ, MacKenzie TA, Curtis KM. The effect of cinnamon on A1C among adolescents with type 1 diabetes. Diabetes Care. 2007;30(4):813-6.
Birks J, Grimley Evans J. Ginkgo biloba for cognitive impairment and dementia. Cochrane Database Syst Rev. 2007;(2):CD003120.
Bright JJ. Curcumin and autoimmune disease. Adv Exp Med Biol. 2007;595:425-51.
Chen Y, Zhu J, Zhang W. Antitumor effect of traditional Chinese herbal medicines against lung cancer. Anticancer Drugs. 2014; 25(9):983-91.
Damery S, Gratus C, Grieve R, et al. The use of herbal medicines by people with cancer: a cross-sectional survey. Br J Cancer. 2011;104(6):927-33.
Dans AM, Villarruz MV, Jimeno CA, et al. The effect of Momordica charantia capsule preparation on glycemic control in type 2 diabetes mellitus needs further studies. J Clin Epidemiol. 2007;60(6):554-9.
Dos Santos-Neto LL, de Vilhena Toledo MA, Medeiros-Souza P, de Souza GA. The use of herbal medicine in Alzheimer's disease-a systematic review. Evid Based Complement Alternat Med. 2006;3(4):441-5.
Ernst E. Herbal Medicine in the Treatment of Rheumatic Diseases. Rheumatic Diseases Clinics of North America. 2011:37(1).
Fang L, Wang Z, Kong W, Feng JG, Ma SL, Lin NM. Anti-tumor and apoptotic effects in vitro and in vivo of a traditional Chinese medicine prescription. Chin Med J (Engl). 2011;124(21):3583-7.
Gratus C, Wilson S, Greenfield SM, Damery SL, Warmington SA, Grieve R, Steven NM, Routledge P. The use of herbal medicines by people with cancer: a qualitative study. Complement Altern Med. 2009 May 14;9:14.
Hasan SS, Ahmed SI, Bukhari NI, Loon WC. Use of complementary and alternative medicine among patients with chronic diseases at outpatient clinics. Complement Ther Clin Pract. 2009 Aug;15(3):152-7.
Izzo AA, Ernst E. Interactions between herbal medicines and prescribed drugs: an updated systematic review. Drugs. 2009;69(13):1777-98.
Jang SH, Kim DI, Choi MS. Effects and treatment methods of acupuncture and herbal medicine for premenstrual syndrome/premenstrual dysphoric disorder: systematic review. BMC Complement Altern Med. 2014;14:11.
Ke F, Yadav PK, Ju LZ. Herbal medicine in the treatment of ulcerative colitis. Saudi J Gastroenterol. 2012;18(1):3-10.
Kennedy DO, Haskell CF, Mauri PL, Scholey AB. Acute cognitive effects of standardised Ginkgo biloba extract complexed with phosphatidylserine. Hum Psychopharmacol. 2007;22(4):199-210.
Knox J, Gaster B. Dietary supplements for the prevention and treatment of coronary artery disease. J Altern Complement Med. 2007;13(1):83-95.
Kraft K. Complementary/Alternative Medicine in the context of prevention of disease and maintenance of health. Prev Med. 2009 May 22. [Epub ahead of print]
Lovera J, Bagert B, Smoot K, et al. Ginkgo biloba for the improvement of cognitive performance in multiple sclerosis: a randomized, placebo-controlled trial. Mult Scler. 2007;13(3):376-85.
Luo H, Lu M, Pei X, Xia Z. Chinese herbal medicine for subacute thyroiditis: a systematic review of randomized controlled trials. J Tradit Chin Med. 2014;34(3):243-53.
Manheimer E, Wieland S, Kimbrough E, Cheng K, Berman BM. Evidence from the Cochrane Collaboration for traditional Chinese medicine therapies. J Altern Complement Med. 2009 Sep;15(9):1001-14.
Marcus DM. Therapy: Herbals and supplements for rheumatic diseases. Nat Rev Rheumatol. 2009 Jun;5(6):299-300.
Mendes E, Herdeiro MT, Pimentel F. The use of herbal medicine therapies by cancer patients. Act Med Port. 2010;23(5):901-8.
Modi AA, Wright EC, Seeff LB. Complementary and alternative medicine (CAM) for the treatment of chronic hepatitis B and C: a review. Antivir Ther. 2007;12(3):285-95.
Moquin B, Blackman MR, Mitty E, Flores S. Complementary and alternative medicine (CAM). Geriatr Nurs. 2009 May-Jun;30(3):196-203. Review.
Oktem M, Eroglu D, Karahan HB, Taskintuna N, Kuscu E, Zeyneloglu HB. Black cohosh and fluoxetine in the treatment of postmenopausal symptoms: a prospective, randomized trial. Adv Ther. 2007;24(2):448-61.
Pham AQ, Kourlas H, Pham DQ. Cinnamon supplementation in patients with type 2 diabetes mellitus. Pharmacotherapy. 2007;27(4):595-9.
Roberts AT, Martin CK, Liu Z, et al. The safety and efficacy of a dietary herbal supplement and gallic acid for weight loss. J Med Food. 2007;10(1):184-8.
Sarris J, Panossian A, Schweitzer I, Stough C, Scholey A. Herbal medicine for depression, anxiety, and insomnia: a review of psychopharmacology and clinical evidence. Eur Neuropsychopharmacol. 2011;21(12):841-60.
Schink M, Troger W, Dabidian A, et al. Mistletoe extract reduces the surgical suppression of natural killer cell activity in cancer patients. a randomized phase III trial. Forsch Komplementarmed. 2007;14(1):9-17.
Sheridan MJ, Cooper JN, Erario M, Cheifetz CE. Pistachio nut consumption and serum lipid levels. J Am Coll Nutr. 2007;26(2):141-8.
Shimazaki M, Martin JL. Do herbal agents have a place in the treatment of sleep problems in long-term care? J Am Med Dir Assoc. 2007;8(4):248-52.
Shrestha S, Freake HC, McGrane MM, Volek JS, Fernandez ML. A combination of psyllium and plant sterols alters lipoprotein metabolism in hypercholesterolemic subjects by modifying the intravascular processing of lipoproteins and increasing LDL uptake. J Nutr. 2007;137(5):1165-70.
Sood A, Barton DL, Bauer BA, Loprinzi CL. A critical review of complementary therapies for cancer-related fatigue. Integr Cancer Ther. 2007;6(1):8-13.
Tamayo C, Diamond S. Review of clinical trials evaluating safety and efficacy of milk thistle (Silybum marianum [L.] Gaertn.). Integr Cancer Ther. 2007;6(2):146-57.
Teas J, Braverman LE, Kurzer MS, Pino S, Hurley TG, Hebert JR. Seaweed and soy: companion foods in Asian cuisine and their effects on thyroid function in American women. J Med Food. 2007;10(1):90-100.
Thomson CA, Rock CL, Caan BJ, et al. Increase in cruciferous vegetable intake in women previously treated for breast cancer participating in a dietary intervention trial. Nutr Cancer. 2007;57(1):11-9.
Valentova K, Stejskal D, Bednar P, et al. Biosafety, antioxidant status, and metabolites in urine after consumption of dried cranberry juice in healthy women: a pilot double-blind placebo-controlled trial. J Agric Food Chem. 2007;55(8):3217-24.
Velasquez MT, Bhathena SJ. Role of dietary soy protein in obesity. Int J Med Sci. 2007;4(2):72-82.
Wang S, Tang Q, Qian W, Fan Y. Meta-analysis of clinical trials on traditional Chinese herbal medicine for treatment of persistent allergic rhinitis. Allergy. 2012;67(5):583-92.
Wojcikowski K, Myers S, Brooks L. Effects of garlic oil on platelet aggregation: a double-blind placebo-controlled crossover study. Platelets. 2007;18(1):29-34.
Yamada J, Hamuro J, Hatanaka H, Hamabata K, Kinoshita S. Alleviation of seasonal allergic symptoms with superfine beta-1,3-glucan: a randomized study. J Allergy Clin Immunol. 2007;119(5):1119-26.
Yang XX, Hu ZP, Duan W, Zhu YZ, Zhou SF. Drug-herb interactions: eliminating toxicity with hard drug design. Curr Pharm Des. 2006;12(35):4649-64.
Zhang M, Liu X, Li J, He L, Tripathy D. Chinese medicinal herbs to treat the side-effects of chemotherapy in breast cancer patients. Cochrane Database Syst Rev. 2007;(2):CD004921.
Zwickey H, Brush J, Iacullo CM, Connelly E, Gregory WL, Soumyanath A, Buresh R. The effect of Echinacea purpurea, Astragalus membranaceus and Glycyrrhiza glabra on CD25 expression in humans: a pilot study. Phytother Res. 2007; [Epub ahead of print].
Last reviewed on: 11/6/2015
Reviewed by: Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network.