Mistletoe Extract for Cancer: What Clinical Trials Show, and the Risks of Replacing Standard Treatment

Stories of people who refused chemotherapy for advanced cancer and instead received injections of mistletoe extract, then outlived grim predictions, have circulated widely online. Such stories are powerful, and the people in them are real. But individual survival stories cannot show whether a treatment works, because cancer outcomes vary widely, and the many people for whom an approach did not work rarely become headlines.

Mistletoe extract is one of the most widely used complementary cancer therapies in Europe, particularly in Germany and Switzerland, and it has been studied in many clinical trials. This article explains what mistletoe therapy is, what the best research shows about survival and quality of life, how it compares with standard treatment for advanced colorectal cancer, and why choosing alternative therapy instead of proven treatment carries serious risks.

What Mistletoe Therapy Is

European mistletoe, Viscum album, is a semi-parasitic plant that grows on trees such as apple, oak, and pine. In the 1920s, Rudolf Steiner, founder of anthroposophic medicine, proposed mistletoe as a cancer treatment, and extracts have been used in European integrative oncology ever since. Products differ by the host tree, the plant parts used, and the manufacturing process, and they are typically injected under the skin several times a week. Some practitioners also give mistletoe by intravenous infusion or directly into tumors, though these routes are less studied.

Mistletoe contains several biologically active compounds, including mistletoe lectins and viscotoxins. Laboratory studies show these can kill cancer cells and stimulate immune activity. The U.S. National Cancer Institute’s summary for health professionals notes that mistletoe extracts are among the most studied complementary therapies for cancer, but that the quality of many studies has been limited and results have been mixed. Raw mistletoe plants and berries are poisonous and should never be eaten.

In the United States, injectable mistletoe extracts are not approved by the FDA for any medical use, including cancer treatment. They can be used only in clinical trials or through some integrative practitioners using imported products.

What Clinical Trials Show

Earlier reviews

A 2008 Cochrane systematic review by Markus Horneber and colleagues examined randomized trials of mistletoe for cancer. It found that the evidence did not support claims of improved survival or tumor response, and that while some trials suggested improved quality of life or reduced side effects of chemotherapy, many had methodological weaknesses. The reviewers called for more rigorous trials.

A survival signal in pancreatic cancer

A 2013 randomized trial in the European Journal of Cancer by Wilfried Tröger and colleagues in Serbia enrolled patients with locally advanced or metastatic pancreatic cancer receiving best supportive care, without chemotherapy. Patients given mistletoe extract had a median overall survival of 4.8 months compared with 2.7 months in the control group. The trial was open-label, without a placebo, and patients did not receive chemotherapy, which was the standard of care in many countries, limiting how widely the findings apply.

The MISTRAL trial

To test this signal more rigorously, Swedish researchers conducted the MISTRAL trial, a double-blind, placebo-controlled study. Results published in 2024 in Deutsches Ärzteblatt International by Karin Wode and colleagues included 290 patients with advanced pancreatic cancer randomly assigned to mistletoe extract or placebo injections three times a week for nine months, alongside standard care. Median overall survival was 7.8 months with mistletoe and 8.3 months with placebo, and the authors concluded that mistletoe extract is unlikely to have a clinically significant effect on overall survival or global quality of life in these patients.

Intravenous mistletoe

Researchers at Johns Hopkins conducted a phase I trial of intravenous mistletoe extract in patients with advanced solid tumors who had progressed on prior chemotherapy. Results published in 2023 by Channing Paller and colleagues found that among 21 patients, side effects such as fatigue and nausea were manageable, five had stable disease for a period, and some had reductions in tumor size, but no patients had an objective response meeting standard criteria. Phase I trials are designed mainly to assess safety and dosing, not effectiveness, so these results justify further research rather than treatment.

How Mistletoe Is Thought to Work

Laboratory research has identified several components of mistletoe that may affect cancer cells and the immune system. Mistletoe lectins can trigger cell death in some cancer cell lines and stimulate immune cells to release signaling molecules. Viscotoxins can damage cell membranes. Some researchers propose that mistletoe’s main effects are immune-modulating, potentially helping the body tolerate treatment or improving well-being. However, effects seen in cell cultures and animal models often do not translate into benefits for patients, which is why clinical trials in people are essential.

What About Quality of Life?

Many supporters of mistletoe therapy argue that its main benefit is improving quality of life, such as reducing fatigue, improving appetite and sleep, and easing side effects of chemotherapy, rather than extending survival. Several trials, many from Europe, have reported improvements in quality-of-life measures. Critics note that many of these trials were not blinded, so patients knew they were receiving mistletoe, which can influence self-reported outcomes. The placebo-controlled MISTRAL trial, which was blinded, did not find a clinically significant improvement in global quality of life. The question remains debated, and patients interested in symptom relief may find better-established options through supportive and palliative care.

Why Survivor Stories Can Mislead

Stories of people who outlived their prognosis after using alternative therapies are emotionally compelling, but several factors make them unreliable as evidence. Survival statistics describe averages; some people with advanced cancer live much longer than average regardless of treatment. Some patients in such stories also received surgery, chemotherapy, or other treatments that may explain their outcomes. Diagnoses and staging can occasionally be uncertain. And the many people who tried the same approach without success are rarely featured. Researchers call this survivorship bias. Only controlled trials, which compare similar patients receiving different treatments, can show whether a therapy improves outcomes.

The Danger of Replacing Standard Treatment

The most important question raised by stories of people who refused chemotherapy is what happens to patients who choose alternative therapies instead of proven treatment. A 2018 study in the Journal of the National Cancer Institute by Skyler Johnson and colleagues used the U.S. National Cancer Database to compare patients with non-metastatic breast, prostate, lung, or colorectal cancer who chose alternative medicine alone with patients who received conventional treatment. Alternative medicine use was associated with 2.5 times the risk of death overall, and with 4.57 times the risk among colorectal cancer patients and 5.68 times among breast cancer patients.

Using mistletoe alongside standard treatment, under an oncologist’s supervision, is very different from using it instead of treatment. Integrative oncology programs at major cancer centers may discuss complementary therapies with patients, but they emphasize that such therapies should support, not replace, evidence-based care.

Advanced Colorectal Cancer Today

According to the National Cancer Institute’s SEER program, the 5-year relative survival rate for colorectal cancer that has spread to distant parts of the body is 16.9 percent, compared with 91.3 percent when the cancer is confined to its original site. These averages hide wide variation. Treatment for metastatic colorectal cancer has advanced considerably and may include combination chemotherapy, drugs targeting specific tumor features, immunotherapy for tumors with particular genetic characteristics such as mismatch repair deficiency, and surgery or other local treatments for some patients whose cancer has spread to a limited number of sites, such as the liver, which can occasionally lead to long-term survival.

Tumor testing for genetic features helps oncologists choose among these options. Because outcomes differ so much between individuals, survival statistics cannot predict what will happen to any one person, which is also why individual success stories, with or without alternative therapies, cannot show what caused a good outcome.

Safety and Side Effects of Mistletoe

Commercially prepared mistletoe extracts used in clinical settings are generally well tolerated. Common side effects include redness, swelling, and itching at the injection site, mild fever, flu-like symptoms, and headache. Allergic reactions, including rare severe reactions, can occur. Because mistletoe may stimulate the immune system, its use alongside immunotherapy or in people with certain conditions, such as some autoimmune diseases, deserves caution, and research on interactions with modern cancer drugs is limited. Products purchased online or from unregulated sources may vary in content and quality.

Talking With Your Oncology Team

Many people with cancer use complementary therapies, often without telling their doctors. Open conversation is safer. Useful questions include: Is there evidence that this therapy helps people with my type and stage of cancer? Could it interact with my treatment? Are there clinical trials I could join? What would I give up if I delayed or declined standard treatment? Many cancer centers have integrative medicine services that can help patients use evidence-based complementary approaches, such as exercise, acupuncture for certain symptoms, and mind-body practices, safely alongside treatment.

Mistletoe in European Practice

In Germany, Switzerland, and some other European countries, mistletoe extracts are among the most frequently used complementary cancer therapies, often prescribed by physicians trained in anthroposophic or integrative medicine and sometimes used alongside chemotherapy. Some hospitals in these countries have integrative oncology departments that use mistletoe as part of supportive care. Regulatory status differs by country. This widespread use has supported a substantial research program, though, as the MISTRAL results show, rigorous trials have not confirmed survival benefits in at least one major cancer type. Researchers continue to study mistletoe in other cancers and settings.

Common Misconceptions

“Mistletoe is a natural chemotherapy.” It has biological activity, but trials have not shown it works like effective chemotherapy against tumors.

“If it is used in European hospitals, it must be proven.” Use reflects tradition and patient demand as well as evidence; rigorous trials have produced mixed results.

“Natural means no side effects.” Injection-site reactions, fever, and allergic reactions occur, and raw mistletoe is poisonous.

“Refusing chemotherapy is just a lifestyle choice.” For many cancers, declining effective treatment substantially increases the risk of death.

“Doctors oppose all complementary therapies.” Many cancer centers offer evidence-based integrative care alongside treatment.

Questions to Ask Before Considering Mistletoe

What evidence exists for mistletoe in my specific type and stage of cancer, and what did the most rigorous trials find? Will it interfere with my chemotherapy, immunotherapy, or other treatments? Who would prescribe and monitor it, and what are their qualifications? What product would be used, and how is its quality ensured? What will it cost, and is it covered? What side effects should I watch for? Are there clinical trials I could join instead? Bringing these questions to both the oncology team and any integrative practitioner helps ensure care is coordinated and decisions are well informed.

Supporting Someone Facing a Difficult Diagnosis

When a friend or family member with cancer considers refusing conventional treatment in favor of alternative therapies, conversations can be difficult. Experts suggest listening to understand their fears and values, such as concerns about side effects, distrust of the medical system, or a desire for control, rather than arguing. Offering to help them get clear information, attend appointments, seek a second opinion, or speak with an integrative oncology service can open options that address their concerns while preserving access to effective treatment. Ultimately, adults have the right to make their own decisions, and respectful support helps ensure those decisions are well informed.

Palliative and Supportive Care

For people with advanced cancer, palliative care specialists focus on relieving symptoms such as pain, fatigue, nausea, breathlessness, and distress, and on supporting patients and families, at any stage of illness and alongside cancer treatment. Research has found that early palliative care can improve quality of life and mood for people with advanced cancer. Patients seeking mistletoe for quality-of-life reasons may find that palliative care offers well-established approaches to the same goals.

Evidence-Based Integrative Oncology

Integrative oncology combines conventional cancer treatment with complementary approaches supported by evidence, aiming to improve symptoms, quality of life, and well-being. Professional groups, including the Society for Integrative Oncology and the American Society of Clinical Oncology, have published joint guidelines on using integrative therapies for problems such as anxiety, depression, pain, and fatigue in people with cancer. Approaches with supportive evidence for specific symptoms include exercise, which can reduce fatigue and improve physical function; acupuncture for certain types of pain and treatment-related nausea; mindfulness-based programs, yoga, and relaxation techniques for anxiety and mood; and music therapy for some symptoms. These guidelines generally do not recommend mistletoe for improving survival, and they emphasize that complementary therapies should be coordinated with the oncology team.

Finding Clinical Trials

Patients interested in mistletoe or other experimental approaches can look for clinical trials, which offer access to new treatments under careful monitoring and contribute to knowledge. The U.S. National Library of Medicine’s ClinicalTrials.gov database lists studies worldwide, including some involving mistletoe. Oncologists and cancer center trial offices can help patients find trials matching their cancer type and stage. Participating in a trial is very different from using an unregulated product outside medical care, because trials include safety monitoring and are designed to answer whether the treatment works.

Cost and Access

In some European countries, mistletoe therapy is widely available and may be covered by health insurance in certain circumstances. In the United States, mistletoe extracts are not FDA-approved for cancer and are usually paid for out of pocket when obtained through integrative practitioners, sometimes at substantial cost over months of treatment. Patients considering such expenses should weigh them against the limited evidence of benefit and ask clearly what outcomes are realistic.

Key Terms

Overall survival: The length of time patients in a study remain alive after starting treatment.

Placebo-controlled trial: A study comparing a treatment with an inactive substance, usually with participants and researchers unaware of assignments.

Integrative oncology: Cancer care that combines conventional treatment with evidence-based complementary approaches.

Alternative medicine: Treatments used instead of conventional medical treatment.

Survivorship bias: Drawing conclusions from cases that succeeded while overlooking those that did not.

The Bottom Line

Mistletoe extract is a widely used complementary therapy in Europe with a long history and active research. Some studies have suggested quality-of-life or survival benefits, but the most rigorous recent trial in advanced pancreatic cancer found no survival advantage, and reviews have found the overall evidence limited. Using mistletoe instead of proven cancer treatment carries serious risks; patients who choose alternative medicine alone have much higher death rates. People interested in mistletoe should discuss it openly with their oncology team, consider clinical trials, and use complementary approaches to support, not replace, effective treatment.

Frequently Asked Questions

Does mistletoe cure cancer?

No reliable evidence shows that mistletoe cures cancer. Some trials suggest quality-of-life benefits, but a large 2024 placebo-controlled trial in advanced pancreatic cancer found no survival benefit.

Is mistletoe therapy legal in the United States?

Injectable mistletoe extracts are not FDA-approved for treating cancer. They are available in clinical trials and through some practitioners using imported products.

Can I use mistletoe with chemotherapy?

Discuss it with your oncologist. Some patients use it as a complement under supervision, but interactions with modern cancer treatments are not well studied.

What is the survival rate for stage IV colon cancer?

The 5-year relative survival for colorectal cancer that has spread to distant sites is about 17 percent according to SEER, but outcomes vary widely with tumor features and treatment.

Is it dangerous to refuse chemotherapy?

Patients who chose alternative medicine instead of conventional treatment had much higher death rates in a large U.S. study. Decisions about treatment should be made with full information from an oncology team.

References

1. National Cancer Institute. Mistletoe Extracts (PDQ), Health Professional Version. cancer.gov
2. Horneber MA, Bueschel G, Huber R, Linde K, Rostock M. Mistletoe therapy in oncology. Cochrane Database of Systematic Reviews. 2008;(2):CD003297. PMID 18425885
3. Tröger W, Galun D, Reif M, et al. Viscum album [L.] extract therapy in patients with locally advanced or metastatic pancreatic cancer: a randomised clinical trial on overall survival. European Journal of Cancer. 2013;49(18):3788–3797. PMID 23890767
4. Wode K, Kienle GS, Björ O, et al. Mistletoe Extract in Patients With Advanced Pancreatic Cancer: a Double-Blind, Randomized, Placebo-Controlled Trial (MISTRAL). Deutsches Ärzteblatt International. 2024;121(11):347–354. PMID 38915151
5. Paller CJ, Wang L, Fu W, et al. Phase I Trial of Intravenous Mistletoe Extract in Advanced Cancer. Cancer Research Communications. 2023;3(2):338–346. PMID 36860652
6. Johnson SB, Park HS, Gross CP, Yu JB. Use of Alternative Medicine for Cancer and Its Impact on Survival. Journal of the National Cancer Institute. 2018;110(1):121–124. PMID 28922780
7. National Cancer Institute SEER Program. Cancer Stat Facts: Colorectal Cancer. seer.cancer.gov

Last updated: October 1, 2026