European mistletoe, famous during the Christmas season, is a semiparasitic plant that grows on trees in Europe and Asia. Its young leafy twigs and flowers were used as an “all-heal” or panacea, said to be helpful for virtually all diseases. The herb is also said to have played a role in Celtic religious celebrations.
Note: American mistletoe, Phoradendron leucarpum, is related to European mistletoe, but it is thought to be more toxic and has not been well studied.
In the 20th century, mistletoe became popular in Germany through the advocacy of a mystic and philosopher named Rudolf Steiner. The school of medicine he founded, anthroposophical medicine, recommended injectable forms of mistletoe as a treatment for cancer. The initial basis for this use was Steiner’s “clairvoyant” insight. Scientific tests were subsequently conducted with somewhat positive results, but current evidence is far from definitive.
Mistletoe extracts show anticancer effects in the test tube.1-5 However, test-tube studies cannot show a treatment effective; only controlled clinical trials can do that. A 2003 review found 10 human trials of injected mistletoe for cancer that met at least minimal scientific standards.6 Unfortunately, even these studies generally suffered from significant weaknesses in design. The review authors noted that the better-designed studies failed to find evidence of benefit, in terms of lengthened remission, improved quality of life, or chance of survival. Subsequent human trials have also failed to reach adequate levels of scientific rigor or clinical relevance and have, therefore, failed to clarify matters.7-10, 21,22,24 Another review of 21 clinical trials found no convincing evidence that mistletoe was effective for cancer survival, tumor response, quality of life, psychological distress, or any other favorable outcomes.23 However, two of the better designed studies did suggest some benefit for breast cancer patients undergoing chemotherapy. A more recent review of 49 22 studies found the addition of mistletoe to standard cancer treatment was associated with improved survival in cancer patients. An analysis restricted to randomized controlled trials, however, showed less of an overall effect.25 In a small randomized trial of 32 patients with gastric cancer, addition of mistletoe to oral chemotherapy improved quality of life and reduced the incidence of diarrhea compared to patients who did not receive mistletoe.26
Oral uses of mistletoe have not undergone significant study. Very weak evidence, too weak to rely upon at all, hints that constituents of mistletoe might potentially offer benefit in diabetes11-14 and colds and flus.15,16 It is commonly stated that oral mistletoe products reduce blood pressure, but there is no scientific evidence to support this belief.
Injectable mistletoe extracts should only be used under the supervision of a physician.
Mistletoe tea can be made by soaking 10-20 g of chopped leaves in 2 cups of water for 8 hours. A typical dose is 1 to 3 cups daily.
In large clinical trials, use of injected pharmaceutical-grade mistletoe products has not been associated with serious adverse effects, although pain at the injection site and mild flu-like symptoms are common. Severe allergic reactions may occur rarely.17
Oral use of a mistletoe product has been associated with hepatitis.18 Mistletoe berries and perhaps the leaves can cause severe toxicity, especially in children.19 American mistletoe may be more toxic than European mistletoe.19,20
Mistletoe is not recommended for use in young children, pregnant or nursing women, or people with severe liver or kidney disease.
1. Urech K, Scher JM, Hostanska K, et al. Apoptosis inducing activity of viscin, a lipophilic extract from Viscum album L. J Pharm Pharmacol. 2005;57:101-9.
2. Harmsma M, Gromme M, Ummelen M, et al. Differential effects of Viscum album extract IscadorQu on cell cycle progression and apoptosis in cancer cells. Int J Oncol. 2004;25:1521-1529.
3. Duong Van Huyen JP, Delignat S, Kazatchkine MD, et al. Comparative study of the sensitivity of lymphoblastoid and transformed monocytic cell lines to the cytotoxic effects of Viscum album extracts of different origin. Chemotherapy. 2003;49:298-302.
4. Yoon TJ, Yoo YC, Kang TB, et al. Antitumor activity of the Korean mistletoe lectin is attributed to activation of macrophages and NK cells. Arch Pharm Res. 2003;26:861-867.
5. Mengs U, Gothel D, Leng-Peschlow E. Mistletoe extracts standardized to mistletoe lectins in oncology: review on current status of preclinical research. Anticancer Res. 2002;22:1399-407.
6. Ernst E, Schmidt K, Steuer-Vogt MK. Mistletoe for cancer? Int J Cancer. 2003;107:262-267.
7. Bock PR, Friedel WE, Hanisch J, et al. Efficacy and safety of long-term complementary treatment with standardized European mistletoe extract ( Viscum album L.) in addition to the conventional adjuvant oncologic therapy in patients with primary non-metastasized mammary carcinoma. Results of a multi-center, comparative, epidemiological cohort study in Germany and Switzerland [in German]. Arzneimittelforschung. 2004;54:456-66.
8. Klopp R, Schmidt W, Werner E, et al. Influence of complementary Viscum album (Iscador) administration on microcirculation and immune system of ear, nose and throat carcinoma patients treated with radiation and chemotherapy. Anticancer Res. 2005;25:601-10.
9. Augustin M, Bock PR, Hanisch J, et al. Safety and efficacy of the long-term adjuvant treatment of primary intermediate- to high-risk malignant melanoma (UICC/AJCC stage II and III) with a standardized fermented European mistletoe ( Viscum album L.) extract. Results from a multicenter, comparative, epidemiological cohort study in Germany and Switzerland. Arzneimittelforschung. 2005;55:38-49.
10. Kovacs E. Effects of Viscum album extract therapy in patients with cancer: relation with interleukin-6, soluble interleukin-6 receptor, and soluble gp130. J Altern Complement Med. 2004;10:241-6.
11. Orhan DD, Aslan M, Sendogdu N, et al. Evaluation of the hypoglycemic effect and antioxidant activity of three Viscum album subspecies (European mistletoe) in streptozotocin-diabetic rats. J Ethnopharmacol. 2005;98:95-102.
12. Onal S, Timur S, Okutucu B, et al. Inhibition of alpha-glucosidase by aqueous extracts of some potent antidiabetic medicinal herbs. Prep Biochem Biotechnol. 2005;35:29-36.
13. Gray AM, Flatt PR. Insulin-secreting activity of the traditional antidiabetic plant Viscum album (mistletoe). JEndocrinol. 1999;160:409-414.
14. Swanson-Flatt SK, Day C, Bailey CJ, Flatt PR. Evaluation of traditional plant treatments for diabetes: studies in streptozotocin-diabetic mice. Acta Diabetologica Latina. 1989;26:51-55.
15. Huber R, Klein R, Ludtke R, et al. Frequency of the common cold in healthy subjects during exposure to a lectin-rich and a lectin-poor mistletoe preparation in a randomized, double-blind, placebo-controlled study. Forsch Komplementarmed Klass Naturheilkd. 2001;8:354-358.
16. Karagoz A, Onay E, Arda N, et al. Antiviral potency of mistletoe ( Viscum album ssp. album) extracts against human parainfluenza virus type 2 in Vero cells. Phytother Res. 2003;17:560-562.
17. Bauer C, Oppel T, Rueff F, et al. Anaphylaxis to viscotoxins of mistletoe ( Viscum album) extracts. Ann AllergyAsthma Immunol. 2005;94:86-89.
18. Harvey J, Colin-Jones DG. Mistletoe hepatitis. Br Med J (Clin Res Ed). 1981;282:186-187.
19. Spiller HA, Willias DB, Gorman SE, Sanftleban J. Retrospective study of mistletoe ingestion. Clin Toxicol 1996;34:405-408.
20. Krenzelok EP, Jacobsen TD, Aronis J. American mistletoe exposures. Am J Emerg Med 1997;15:516-520.
21. 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;14:9-17.
22. Grossarth-Maticek R, Ziegler R. Prospective controlled cohort studies on long-term therapy of cervical cancer patients with a mistletoe preparation (Iscador). Forsch Komplementarmed. 2007;14:140-147.
23. Horneber MA, Bueschel G, Huber R, Linde K, Rostock M. Mistletoe therapy in oncology. Cochrane Database of Systematic Reviews. 2008;(2): CD003297.
24. Grossarth-Maticek R, Ziegler R. Randomized and non-randomized prospective controlled cohort studies in matched pair design for the long-term therapy of Corpus uteri cancer patients with a mistletoe preparation (Iscador). Eur J Med Res. 2008;13:107-120.
25. Ostermann T, Raak C, Büssing A. Survival of cancer patients treated with mistletoe extract (Iscador): a systematic literature review. BMC Cancer. 2009;9:451.
26. Kim KC, Yook JH, et al. Quality of life, immunomodulation and safety of adjuvant mistletoe treatment in patients with gastric carcinoma - a randomized, controlled pilot study. BMC Complement Altern Med. 2012;12:172.
Last reviewed December 2015 by EBSCO CAM Review Board Last Updated: 12/15/2015