This article was originally published by the National Cancer Institute here:


Questions and Answers About Mistletoe

  1. What is mistletoe?Mistletoe is a semiparasitic plant that grows on trees, such as apple, oak, maple, elm, pine, and birch. It has been used for hundreds of years to treat medical conditions such as epilepsy, hypertension, headaches, menopausal symptoms, infertility, arthritis, and rheumatism. Mistletoe is one of the most widely studied complementary and alternative medicine therapies for cancer. In Europe, mistletoe extracts are among the most prescribed therapies for cancer patients.Mistletoe products vary, depending on the following factors:
    • The type of host tree on which the mistletoe grows.
    • The species of mistletoe.
    • The type of extract used and if it is made with homeopathic methods.
    • The time of year the plant is picked.
    • The company that makes the product.
    Mistletoe extracts are made in water-based solutions or solutions of water and alcohol. Mistletoe products may be named according to the type of tree on which the plant grows. For example, IscadorM is from apple trees, IscadorP comes from pine trees, IscadorQu is from oak trees, and IscadorU comes from elm trees.
  2. How are mistletoe extracts given?Mistletoe extracts are usually given by an injection under the skin (subcutaneous). Less common ways to give mistletoe include by mouth, into a vein (intravenous or IV), into the pleural cavity, or into a tumor.
  3. What laboratory or animal studies have been done using mistletoe extracts?In laboratory studies, tumor cells are used to test a substance to find out if it is likely to have any anticancer effects. In animal studies, tests are done to see if a drug, procedure, or treatment is safe and effective in animals. Laboratory and animal studies are done before a substance is tested in people. Laboratory and animal studies have tested the effects of mistletoe extracts in laboratory experiments. See the Laboratory/Animal/Preclinical Studies section of the health professional version on Mistletoe Extracts for information on laboratory and animal studies done using mistletoe extracts.
  4. Have any studies of mistletoe extracts been done in people? Most clinical trials using mistletoe extracts to treat cancer have been done in Europe. Many studies use mistletoe as adjuvant therapy in patients with cancer. Although these trials have reported mistletoe extracts to be effective, weaknesses have been reported.
    • Size of trial.
    • Lack of patient information.
    • Lack of dose information.
    • Study design.
    Findings from studies with large numbers of patients reported the following:In 2002, the National Center for Complementary and Integrative Health (NCCIH) and the National Cancer Institute (NCI) enrolled patients in a phase I clinical trial of a mistletoe extract and gemcitabine in patients with advanced solid tumors. This combination showed low toxicity and no botanicaldrug interactions were reported.Reviews of combined clinical trialsReviews have looked at the effects of mistletoe on quality of life, survival, and symptom relief in different types of cancer:
    • Quality of life was measured in a review that included 26 randomized clinical trials. Of these, 22 trials showed patients had improved quality of life. Chemotherapy-related fatigue, nausea and vomiting, depression, emotional well-being, and concentration improved. All 10 nonrandomized, controlled clinical trials reviewed also reported the same benefits. Some of the studies were well designed, while others had weaknesses.
    • Tumor response, quality of life, and psychological distress were measured in a review of 21 randomized clinical trials in patients with different types of cancer. Mistletoe extracts were used either alone, with chemotherapy, or with radiation therapy. Most of the studies reported benefits for patients, although this review had weaknesses in design and size.
    • Quality of life and survival were measured in a review of 10 randomized clinical trials which used mistletoe extracts in patients with different types of cancer. There was no difference in survival or quality of life measures in patients who received mistletoe compared to those who did not.
  5. Have any side effects or risks been reported from mistletoe?Few serious side effects have been reported from the use of mistletoe extracts. Side effects include soreness and inflammation at injection sites, headache, fever, and chills.One review reported that treatment was not found to lessen immune system response. High doses of mistletoe damaged the liver in some cases, but damage was correctable. Another review of clinical trials reported adverse effects that included circulatory problems, thrombophlebitis, swelling of lymph nodes, and allergic reactions.A few cases of severe allergic reactions, including anaphylactic shock, have been reported.
  6. Is mistletoe approved by the U. S. Food and Drug Administration (FDA) for use as a cancer treatment in the United States?The U.S. Food and Drug Administration (FDA) has not approved the use of mistletoe as a treatment for cancer or any other medical condition.

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