Background
- European mistletoe is a parasitic plant that grows on several types of common trees such as apple, oak, pine, and elm. European mistletoe is different from American mistletoe, the type of mistletoe that grows in the United States and is used as a holiday decoration.
- European mistletoe has been used for centuries in traditional medicine for a variety of conditions, including seizures, headaches, and menopause symptoms. Today, European mistletoe is promoted as a treatment for cancer.
- In Europe, European mistletoe extracts that are given by injection are sold as prescription drugs. European mistletoe may also be taken orally (by mouth) as a dietary supplement. The U.S. Food and Drug Administration has not approved the use of European mistletoe as a treatment for cancer or any other medical condition.
How Much Do We Know?
- Although European mistletoe has been studied for cancer, its effects are not well understood because much of the research has been of poor quality.
What Have We Learned?
- There have been clinical trials of European mistletoe for cancer, mostly in Europe. Although some trials indicated that European mistletoe improved survival or quality of life, almost all of the trials had major weaknesses that raise doubts about their findings. These weaknesses have included small numbers of patients, lack of information about the patients, lack of information about the dose of European mistletoe, and problems with the design of the studies.
- The National Center for Complementary and Integrative Health (NCCIH) and the National Cancer Institute performed a preliminary trial to evaluate the safety of injected European mistletoe extract in combination with a cancer drug in patients with advanced cancer. It showed that patients could tolerate the herb/drug combination.
- European mistletoe is not a proven cancer treatment. It should not be used as a treatment for cancer outside of clinical trials.
What Do We Know About Safety?
- European mistletoe berries and leaves can cause serious harmful effects when taken orally (by mouth).
- European mistletoe is probably unsafe for use during pregnancy. Little is known about whether it’s safe for use while breastfeeding.
- Injected European mistletoe extract may cause soreness and inflammation at the injection site, headache, fever, and chills. A few severe allergic reactions have been reported.
Keep in Mind
- Take charge of your health—talk with your health care providers about any complementary health approaches you use. Together, you can make shared, well-informed decisions.
NCCIH Clearinghouse
The NCCIH Clearinghouse provides information on NCCIH and complementary and integrative health approaches, including publications and searches of Federal databases of scientific and medical literature. The Clearinghouse does not provide medical advice, treatment recommendations, or referrals to practitioners.
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PubMed®
A service of the National Library of Medicine, PubMed® contains publication information and (in most cases) brief summaries of articles from scientific and medical journals. For guidance from NCCIH on using PubMed, see How To Find Information About Complementary Health Approaches on PubMed.
Website: https://pubmed.ncbi.nlm.nih.gov/
Office of Dietary Supplements (ODS), National Institutes of Health (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 (such as Dietary Supplements: What You Need To Know) and fact sheets on a variety of specific supplement ingredients and products (such as vitamin D and multivitamin/mineral supplements).
Website: https://ods.od.nih.gov
Email: ods@nih.gov (link sends email)
Key References
- European mistletoe. Natural Medicines website. Accessed at naturalmedicines.therapeuticresearch.com on November 11, 2019. [Database subscription].
- Horneber MA, Bueschel G, Huber R, et al. Mistletoe therapy in oncology. Cochrane Database of Systematic Reviews. 2008;(2):CD003297 [edited 2010]. Accessed at https://www.cochranelibrary.com on December 17, 2019.
- Mansky PJ, Wallerstedt DB, Sannes TS, et al. NCCAM/NCI phase I study of mistletoe extract and gemcitabine in patients with advanced solid tumors. Evidence-Based Complementary and Alternative Medicine. 2013;2013:964592.
- National Cancer Institute. Mistletoe Extracts (PDQ). National Cancer Institute website. Accessed at https://www.cancer.gov/about-cancer/treatment/cam/patient/mistletoe-pdq on December 17, 2019.