National Center for Complementary and Alternative Medicine (NCCAM)

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What You Should Know About 5 Popular Herbs

Herbal or botanical supplements are widely marketed and readily available, often sold as dietary supplements. However, the scientific evidence available about the safety or effectiveness of herbal supplements varies quite a bit. In some cases, there is limited evidence to support a product’s use, while in others, evidence has uncovered safety concerns, or is insufficient to draw clear conclusions. Because of this variability, you should carefully review the available information and talk to your health care providers before using a specific product.

Out of the more than 3 million visitors who came to NCCAM’s Web site in 2012, the majority were looking for information on specific herbs and botanicals. The top five searched-for herbs of 2012 that brought people to our site are evening primrose oil, St. John’s wort, fenugreek, echinacea, and aloe vera. Here are some things you should know about these popular herbal supplements:

  1. Evening Primrose Oil. Although evening primrose oil has been used as a folk or traditional remedy for eczema, rheumatoid arthritis, and menopausal symptoms, there is not enough evidence to support the use of evening primrose oil for these conditions.
      
  2. St. John’s Wort. Study results on the effectiveness of St. John’s wort for depression are conflicting. While there may be public interest in St. John’s wort to treat depression, the Food and Drug Administration has not approved its use as an over-the-counter or prescription medicine for depression. Importantly, St. John’s wort is known to affect metabolism of a number of drugs, such as antiviral medicines, antidepressants, birth control pills, and certain anti-seizure medicines, and can cause serious side effects.
      
  3. Fenugreek. Fenugreek is sometimes used as a folk or traditional remedy for diabetes and loss of appetite, and to stimulate milk production in breastfeeding women. However, there is not enough scientific evidence to support the use of fenugreek for these or any health condition. Given its historical use for inducing childbirth, women should use caution when taking fenugreek during pregnancy.
      
  4. Echinacea. Overall, the scientific evidence on echinacea for colds is inconclusive. There is limited evidence from some studies that some echinacea preparations might reduce the length or severity of colds in adults, but results from four NCCAM-funded clinical trials of echinacea for colds all indicated that echinacea did not reduce the length or severity of cold symptoms. Few side effects have been reported in clinical trials of echinacea, but some people may have allergic reactions.
      
  5. Aloe Vera.
    Topical use: A few small studies suggest that topical aloe gel may help heal burns and abrasions. In general, topical use of aloe appears to be safe; one study, however, showed that aloe gel may inhibit healing of deep surgical wounds.
    Oral use: Aloe latex contains strong laxative compounds, and in 2002, the U.S. Food and Drug Administration required that all over-the-counter aloe laxative products be removed from the U.S. market or reformulated because the companies that manufactured them did not provide the necessary safety data.