Mistletoe extracts are prepared from the European mistletoe plant (Viscum album). Mistletoe extracts are a main component of anthroposophic cancer care, where they are administered subcutaneously at increasing doses depending on the individual patient. They are also available as phytotherapeutic preparations standardised for mistletoe lectin content and administered at fixed doses. Use of mistletoe extracts is primarily aimed at improving quality of life and reducing treatment-related adverse events. It has also been investigated as a potential anticancer treatment.
Quality of life and treatment-related adverse events
Across three systematic reviews, mistletoe extracts were associated with moderate improvements in overall quality of life and cancer-related fatigue. Benefits were observed across several symptoms and functional outcomes related to quality of life but not consistently across all outcomes. The confidence in the finding is however low, due to high risk of bias, heterogeneity, and reliance on older studies.
Survival-related outcomes
Evidence from two systematic reviews suggests that mistletoe therapy may improve overall and event-related survival outcomes, with some meta-analyses reporting significant benefits. A third SR found no clear benefits found for perioperative mortality, recurrence or tumour response. The confidence in these results is reduced due to the methodological limitations of the included trials.
Safety
Mistletoe extracts appear to be generally well tolerated in cancer patients, with the most common adverse events being mild local injection-site reactions, low-grade fever, and flu-like symptoms. Serious adverse events are rare but include anaphylaxis, angioedema, severe inflammatory reactions. Potential interactions are primarily theoretical and involve immunomodulatory agents.
Description
Mistletoe extract is a liquid preparation made from the leaves, stems, and berries of the European mistletoe plant (Viscum album). It is a hemiparasitic plant which grows on several types of trees.
In anthroposophically-extended medicine, mistletoe constitutes the central component of a broader treatment regimen; outside the context of anthroposophic care it is used as a single herbal treatment agent.
Available preparations of various forms of mistletoe extracts include ABNOBAViscum® (Abnoba), Helixor® (Helixor), Iscador® (Iscador AG), Iscucin® (Wala), Isorel® (LUKAS).
Ingredients and quality issues
Mistletoe extracts contain a diverse range of pharmacologically active substances. The main anticancer compounds isolated from Viscum species are lectins and viscotoxins, phenolic compounds, triterpene acids and non-polar compounds (Szurpnicka 2020).
The extracts contain ingredients in varying concentrations depending on the species of the host tree, the time of year harvested, and the pharmaceutical process used to prepare the extracts (Becker 2000; Rostock 2020). Some preparations are standardized to the content of mistletoe lectins.
Alleged indications
The use of mistletoe is primarily aimed at improving quality of life through reduction of chemotherapy-related adverse effects and tumour-related complaints in a supportive care context. (Kienle 2011) In addition, some proponents postulate that mistletoe supports cancer remission and survival.
Application and dosage
Mistletoe extracts are used in both adjuvant and palliative cancer treatment, mainly alongside conventional tumour therapies. There are two main approaches for their production and clinical use (Kienle 2003; Rostock 2020):
- Anthroposophical mistletoe preparations: Produced under anthroposophical pharmaceutical guidelines, these are based on multiple active compounds working additively or synergistically. Dosages typically increase gradually, tailored to the patient’s condition, injection site reaction, and body temperature regulation. Some physicians also consider immunological parameters when adjusting doses.
- Phytotherapeutic preparations: Standardised for mistletoe lectin content (e.g. Lektinol), these are administered at a fixed dose.
Mistletoe is most commonly injected subcutaneously, though other routes (e.g. intravenous, intrapleural, intra-/peritumoural) are also used. The choice of host tree, extract type, and dosing depend on the desired immune response, tumour type, disease stage, and antitumour treatment. Subcutaneous injections are generally given 2–3 times per week, with treatment lasting from weeks to years. Due to variation in active compounds, general dosing recommendations are not applicable.
Legal status
The Herbal Medicinal Products Committee (HMPC) of the European Medicines Agency stated that “oncological use of Viscum album falls outside the scope of the Directive 2001/83/EC as amended for traditional herbal medicinal products and the evaluation with respect to well-established use is currently not possible” EMA 2009
In Europe, regulation varies between countries. In Germany, Switzerland, and Austria, mistletoe preparations are approved for adjuvant therapy in oncology by prescription. In Switzerland basic statutory health insurance covers prescription mistletoe preparations such as Helixor and Iscador when prescribed by a licensed physician. In Germany, since August 2026 homeopathic and anthroposophic preparations are no longer reimbursed by statutory health insurance; this includes mistletoe preparations which were previously reimbursed for the palliative cancer treatment. (GVK 2026)
In other countries, mistletoe is generally not approved as a cancer treatment by agencies like the FDA and is not reimbursed by public healthcare programs. (PDQ 2024)
This evidence summary is based on systematic reviews (SRs) published between January 2021 and October 2026, which were retrieved through systematic literature searches. It assesses whether mistletoe extracts improve various cancer-related symptoms and outcomes:
CAM Cancer appraised the quality of the SRs with the AMSTAR2 tool and only included SRs of moderate or high quality, while SRs of low or critically low quality were excluded. The full description of the included studies can be viewed in the evidence tables [link].
A multicentre observational study including 1,923 cancer patients and safety SR found mistletoe to be safe (Steele 2014). The systematic reviews evaluated for this summary reported mostly minor side effects such as local reactions at the injection site and flu-like symptoms (Pelzer 2022, Freuding 2019, Cogo 2023, Loef 2023) but safety was not systematically assessed in the included trials. The most recent large and rigorous RCT did not report any safety concerns (Wode 2024).
Adverse effects
Common and mild
Most adverse events are related to immune stimulation and occur particularly during treatment initiation or dose escalation. Local injection-site reactions (redness, swelling, warmth, itching, pain, induration); mild fever or increased body temperature; flu-like symptoms; chills; fatigue; headache; nausea or gastrointestinal discomfort. These reactions are usually mild to moderate, dose-dependent, and resolve spontaneously or after dose adjustment. (NatMed 2026;) Local reactions are considered desirable as they reflect immune stimulation and guide the dosing schedule. (mistletoe.org, Loef 2022; Pelzer 2022)
Less common adverse events include urticaria (hives), generalized rash, diarrhoea, weakness, dizziness. Most cases are reversible after discontinuation or dose reduction.
Rare serious adverse events
Although uncommon, serious hypersensitivity reactions have been reported severe allergic reactions (anaphylaxis), pseudo-allergic reactions, angioedema (swelling of the face, throat, or mucous membranes). (NatMed 2026)
Contraindications, precautions, warnings
Available data are preliminary and limited. Absolute contraindications include known hypersensitivity to mistletoe or its constituents.
Pregnancy and lactation: Not enough safety data are available. Although no clinical trials have specifically evaluated the emmenagogue effects of Viscum album, some reviews and monographs (Grigoriu 2021) advise caution during pregnancy due to the presence of compounds with potential emmenagogue activity.
Children: Not enough data available.
Relative / theoretical contraindications: Treatment is generally postponed during acute infection, high fever, significant inflammatory disease flare. Theoretical contraindications have been hypothesized in cases of fever, tachycardia, hyperthyroidism, central nervous system conditions, and autoimmune diseases. However, these contraindications are theoretical, and some animal and human studies appear to contradict them (Oei 2019, Szurpnicka 2020, Szurpnicka 2019).
Interactions
Evidence for clinically significant interactions is limited, but several theoretical or case-based concerns exist for potential interaction with immunosuppressants, anticoagulants and antiplatelet drugs.
Available clinical studies have generally not demonstrated clinically relevant negative interactions with chemotherapy, radiotherapy, targeted therapies, immune checkpoint inhibitors. However, evidence quality is variable.
Potential herb–drug interactions are hypothesized based on observed human effects and include hypotensive drugs (Poruthukaren, 2013), and immunosuppressants (Hajto 1986).
CYP: Single in vitro studies indicate no herb–drug interaction (Schink 2017, Doehmer 2011).
P-glycoprotein: A single study detected inhibitory activity in vitro (Nicoletti 2023). Additional studies are needed.
Oxidant chemotherapy: In vitro, no interaction was observed (doxorubicin, gemcitabine, docetaxel, mitoxantrone) (Weissenstein 2014).
Immune checkpoint inhibitors: In cancer patients, no increase in adverse events was observed (Thronicke 2017, Schad 2024); however, specific interaction studies are lacking.
Monoclonal antibody: A retrospective study conducted in cancer patients suggests low risk of interaction (Schad 2018; Weissenstein 2016).
Cogo E, Elsayed M, Bhardwaj S, Cooley K, Aycho C, Liang V, Papadogianis P, Psihogios A, Seely D. Mistletoe Extracts during the Oncological Perioperative Period: A Systematic Review and Meta-Analysis of Human Randomized Controlled Trials. Curr Oncol. 2023 Sep 6;30(9):8196-8219. doi: 10.3390/curroncol30090595. [QoL not primary outcome]
Doehmer J, Eisenbraun J. Assessment of extracts from mistletoe (Viscum album) for herb-drug interaction by inhibition and induction of cytochrome P450 activities. Phytother Res. 2012 Jan;26(1):11-7. doi: 10.1002/ptr.3473.
EMA, European Medicines Agency. Final Assessment Report on Viscum album https://www.ema.europa.eu/en/documents/herbal-report/final-assessment-report-viscum-album-l-herba_en.pdf, 2009. Accessed October 2026.
Freuding M, Keinki C, Kutschan S, Micke O, Buentzel J, Huebner J. Mistletoe in oncological treatment: a systematic review : Part 2: quality of life and toxicity of cancer treatment. J Cancer Res Clin Oncol. 2019 Apr;145(4):927-939. doi: 10.1007/s00432-018-02838-3.
Hajto T. Immunomodulatory effects of Iscador: a Viscum album preparation. Oncology 1986; 43(Suppl): 51-65.
Hofinger J, Kaesmann L, Buentzel J, Scharpenberg M, Huebner J. Systematic assessment of the influence of quality of studies on mistletoe in cancer care on the results of a meta-analysis on overall survival. J Cancer Res Clin Oncol. 2024 Apr 29;150(4):219. doi: 10.1007/s00432-024-05742-1. [low quality according to AMSTAR2]
Kienle GS, Grugel R, Kiene H. Safety of higher dosages of Viscum album L. in animals and humans--systematic review of immune changes and safety parameters. BMC Complement Altern Med. 2011 Aug 28;11:72. doi: 10.1186/1472-6882-11-72.
Loef M, Paepke D, Walach H. Quality of Life in Breast Cancer Patients Treated With Mistletoe Extracts: A Systematic Review and Meta-Analysis. Integr Cancer Ther. 2023 Jan-Dec;22:15347354231198074. doi: 10.1177/15347354231198074.
Loef M, Walach H. Survival of Cancer Patients Treated with Non-Fermented Mistletoe Extract: A Systematic Review and Meta-Analysis. Integr Cancer Ther. 2022 Jan-Dec;21:15347354221133561. doi: 10.1177/15347354221133561.
NatMed Pro 2026. Natural Medicines. European Mistletoe. Online database, requires subscription. Accessed 11, 2025.
Nicoletti, M. (2023). The Antioxidant Activity of Mistletoes (Viscum album and Other Species). Plants, 12(14), 2707. https://doi.org/10.3390/plants12142707.
Oei SL, Thronicke A, Kröz M, Matthes H, Schad F. Use and Safety of Viscum album L Applications in Cancer Patients With Preexisting Autoimmune Diseases: Findings From the Network Oncology Study. Integr Cancer Ther. 2019 Jan-Dec;18:1534735419832367. Doi: 10.1177/1534735419832367.
Ostermann T, Appelbaum S, Poier D, Boehm K, Raak C, Büssing A. A Systematic Review and Meta-Analysis on the Survival of Cancer Patients Treated with a Fermented Viscum album L. Extract (Iscador): An Update of Findings. Complement Med Res. 2020;27(4):260-271. Ostermann 2020
PDQ® Integrative, Alternative, and Complementary Therapies Editorial Board. PDQ Mistletoe Extracts. Bethesda, MD: National Cancer Institute. Updated 11th June 2024. Available at: https://www.cancer.gov/about-cancer/treatment/cam/patient/mistletoe-pdq. Accessed October 2026.
Pelzer F, Loef M, Martin DD, Baumgartner S. Cancer-related fatigue in patients treated with mistletoe extracts: a systematic review and meta-analysis. Support Care Cancer. 2022 Aug;30(8):6405-6418. doi: 10.1007/s00520-022-06921-x. Epub 2022 Mar 3.
Poruthukaren KJ, Palatty PL, Baliga MS, Suresh S. Clinical evaluation of Viscum album mother tincture as an antihypertensive: a pilot study. J Evid Based Complementary Altern Med. 2014 Jan;19(1):31-5. Doi: 10.1177/2156587213507726.
Rostock M. Die Misteltherapie in der Behandlung von Patienten mit einer Krebserkrankung [Mistletoe in the treatment of cancer patients]. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz. 2020 May;63(5):535-540. German. doi: 10.1007/s00103-020-03122-x. PMID: 32211937.
Schad F, Axtner J, Kröz M, Matthes H, Steele ML. Safety of Combined Treatment With Monoclonal Antibodies and Viscum album L Preparations. Integr Cancer Ther. 2018 Mar;17(1):41-51. doi: 10.1177/1534735416681641.
Schad F, Thronicke A, Hofheinz RD, Matthes H, Grah C. Patients with Advanced or Metastasised Non-Small-Cell Lung Cancer with Viscum album L. Therapy in Addition to PD-1/PD-L1 Blockade: A Real-World Data Study. Cancers (Basel). 2024 Apr 22;16(8):1609. doi: 10.3390/cancers16081609.
Schink M, Dehus O. Effects of mistletoe products on pharmacokinetic drug turnover by inhibition and induction of cytochrome P450 activities. BMC Complementary and Alternative Medicine. 2017 Dec;17(1):521. DOI: 10.1186/s12906-017-2028-1. PMID: 29202738; PMCID: PMC5715639.
Steele ML, Axtner J, Happe A, Kröz M, Matthes H, Schad F. Adverse Drug Reactions and Expected Effects to Therapy with Subcutaneous Mistletoe Extracts (Viscum album L.) in Cancer Patients. Evid Based Complement Alternat Med. 2014;2014:724258. doi: 10.1155/2014/724258.
Szurpnicka A, Kowalczuk A, Szterk A. Biological activity of mistletoe: in vitro and in vivo studies and mechanisms of action. Arch Pharm Res. 2020 Jun;43(6):593-629. doi: 10.1007/s12272-020-01247-w.
Szurpnicka A, Zjawiony JK, Szterk A. Therapeutic potential of mistletoe in CNS-related neurological disorders and the chemical composition of Viscum species. J Ethnopharmacol. 2019 Mar 1;231:241-252. doi: 10.1016/j.jep.2018.11.025.
Thronicke A, Steele ML, Grah C, Matthes B, Schad F. Clinical safety of combined therapy of immune checkpoint inhibitors and Viscum album L. therapy in patients with advanced or metastatic cancer. BMC Complement Altern Med. 2017 Dec 13;17(1):534. doi: 10.1186/s12906-017-2045-0.
Vella R, Giardino A, Pizzocaro E, Frigerio I, Bannone E, Vieni S, Butturini G. Unconventional Treatments for Pancreatic Cancer: A Systematic Review. Cancers (Basel). 2025 Apr 25;17(9):1437. doi: 10.3390/cancers17091437.
Weissenstein U, Kunz M, Urech K, Baumgartner S. Interaction of standardized mistletoe (Viscum album) extracts with chemotherapeutic drugs regarding cytostatic and cytotoxic effects in vitro. BMC Complement Altern Med. 2014 Jan 8;14:6. doi: 10.1186/1472-6882-14-6.
Weissenstein U, Kunz M, Urech K, Regueiro U, Baumgartner S. Interaction of a standardized mistletoe (Viscum album) preparation with antitumor effects of Trastuzumab in vitro. BMC Complement Altern Med. 2016 Aug 4;16:271. doi: 10.1186/s12906-016-1246-2.
Wode K, Björ O, Klein R, Elander NO, Fransson P, Henriksson R, Sharp L, Scheibling U, Johansson B, Hök Nordberg J, Kienle GS. Mistletoe extract in patients with advanced pancreatic cancer: Health-related quality of life in a double-blind, randomized, placebo-controlled trial (MISTRAL). Palliat Med. 2026 Jul;40(7):1059-1076. doi: 10.1177/02692163261437609.
Wode K, Kienle GS, Björ O, Fransson P, Sharp L, Elander NO, Bernhardson BM, Johansson B, Edwinsdotter Ardnor C, Scheibling U, Hök Nordberg J, Henriksson R. Mistletoe Extract in Patients With Advanced Pancreatic Cancer: a Double-Blind, Randomized, Placebo-Controlled Tial (MISTRAL). Dtsch Arztebl Int. 2024 May 31;121(11):347-354. doi: 10.3238/arztebl.m2024.0080.
Citation
CAM Cancer Consortium. Mistletoe (Viscum album) [online document], October 2026.
Document history
Last update in September 2026 by the CAM Cancer Collaboration. Previously updated by Mirjam Wüsthof in March 2020 and January 2015. Summary first published in March 2011, authored by Edzard Ernst.
Photo: mp11774686 from Mostphotos.com, licence via UiT The Arctic University of Norway.
