For most people, mistletoe brings to mind none other than Christmas. But besides serving as a festive holiday decoration, did you know that mistletoe is also used in herbal medicine and has been for hundreds of years?
It’s a little known fact that there is actually more than one type of mistletoe; in fact, it’s believed over 100 different mistletoe species grow around the world. A few of these are commonly harvested for their medicinal purposes.
American mistletoe (Phoradendron flavescen) is the type that grows in the United States and is used as a romantic holiday decoration, while European mistletoe (Viscum album) is the species that has been used for centuries in traditional herbal medicine. A third species of mistletoe (Loranthus ferrugineus) is less common but used by some to treat high blood pressure and gastrointestinal complaints. Other species, including Japanese mistletoe (Taxillus yadoriki Danser), are known for their many antimicrobial and antioxidant properties.
When it comes to health-promotion and preventing common conditions, what is mistletoe used for? According to the National Center for Complimentary and Integrative Health (NCCIH), some of the many ailments that mistletoe may help treat include seizures, headaches, arthritis symptoms and potentially even cancer. While it may have been considered a top herb for healing throughout history and currently in Europe, there’s not much evidence showing it definitely works … and some that indicates it may be dangerous.
What Is Mistletoe?
Mistletoe is a member of the Viscaceae plant family and is considered an evergreen hemiparasitic plant. As a parasitic plant, it latches on to trees and feeds off of them.
It is harvested for its berries, leaves and stems. Herbalists then use these to make herbal extracts that have certain physiological effects. The European plant, the type used as a supplement/medicine, grows on common trees such as apple, oak, pine and elm trees. Mistletoe plants form clusters or “bushes” on these trees that then form into mature flowers and then bunches of white, sticky berries during cooler months.
The International Academy of Herbal Arts and Sciences states on their website that “mistletoe burrows roots into the inner wood of trees and feeds from their sap. A heavy infestation with mistletoe can kill branches of the host plant or even the entire host.” This is one reason why mistletoe has earned a reputation as being “poisonous.”
Some of the most recognized species include: Viscum, Phoradendron, Arceuthobium, Peraxilla, Loranthus, Amylotheca, Amyema, Taxillus, Psittacanthus and Scurrula. Mistletoe plants are grown around the world, distributed across Europe, America, Asia and Africa to Australia and New Zealand.
Once dried and made into an extract, it is typically given as an injection. It can, however, also be taken by mouth as a capsule/supplement and consumed as a tea/tincture. Studies have identified different kinds of free radical-scavenging antioxidant, antimicrobial and anti-inflammatory constituents within various species, including:
- Terpenoids and/or steroids
- Acidic compounds
- Gallic acid
Is Mistletoe Poisonous? Mistletoe Dangers & Precautions
What do we know about the effectiveness and safety of mistletoe? Is real mistletoe poisonous or potentially harmful?
- It’s well-known that parts of the plant, including the berries and leaves, can cause serious side effects when consumed orally. Poisoning can also occur if you drink tea created from the plant or its leaves and berries. The poisonous ingredient found in mistletoe is called phoratoxin. Symptoms are most likely to occur after ingesting the leaves and usually last one to three days.
- There are also potential side effects associated with injections. Side effects that can be caused by mistletoe extract injections can include: soreness, inflammation at the injection site, headache, fever, chills, skin rash and rarely severe allergic reactions.
- Other potential adverse reactions include vomiting, diarrhea, cramping and liver damage if used long-term.
- Consuming small amounts, such as taking three berries or two leaves by mouth, has mostly been shown to be safe. Larger doses pose the greatest risk for serious side effects.
- All of that being said, mistletoe when used as medicine seems to be generally safe. According to a 2018 statement published by the PDQ Integrative, Alternative, and Complementary Therapies Editorial Board, “few side effects have been reported from the use of mistletoe extracts.”
Mistletoe has been used for centuries in traditional medicine and medicinally in Europe since the 1920s, but limited research exists on its effects. Most of the clinical trials focusing on mistletoe that are available have been conducted in Europe. Some trials have found evidence that mistletoe can help improve survival or quality of life in cancer patients; however, the vast majority of trials have had “major weaknesses that raise doubts about their findings.”
Additional controlled trials with larger sample sizes of patients are still needed to clear up information about the effects of mistletoe and what the optimal dose may be. Currently in the United States, mistletoe is only used in clinical trials and not otherwise indicated for use.
The NCCIH and the National Cancer Institute have completed 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 seemed tolerate the herb/drug combination; however, future studies are still being designed to evaluate mistletoe’s effectiveness. That means that for now, it is still considered an unproven cancer treatment.
Mistletoe should not be used during pregnancy, since there are no studies to show it’s safe and some that suggest it can cause changes in the uterus that increase miscarriage risk. It also shouldn’t be used by anyone with an autoimmune disease since it might cause the immune system to become more active or anyone being treated for diabetes or heart disease/high blood pressure since it can modify glucose/blood sugar levels.
Because it’s controversial and capable of causing adverse effects, it’s best to consult with a healthcare practitioner before taking mistletoe.
6 Potential Mistletoe Health Benefits
1. Potentially Helpful for Cancer
Extracts are given by injection in Europe, where mistletoe is currently sold as a prescription drug, most often for cancer. Today, mistletoe extracts are the most frequently prescribed unconventional cancer therapies in Germany and some other European countries. Even though it has been used in Europe since the 1920s, the U.S. Food and Drug Administration has not approved it as a treatment for any condition, including cancer.
What does mistletoe do to possibly help fight cancer? In certain studies, it has been shown to stimulate the immune system and kill certain cancer cells; however, these effects have mostly been observed in test tubes and not in humans. A number of in-vitro studies have reported immunostimulatory, cytotoxic and proapoptotic effects. Unfortunately, though, almost all studies have had at least one major weakness that has made researchers question their reliability. Some have shown that mistletoe extract demonstrates the ability to block the formation of new vessels, cutting off the blood supply to tumors.
There is some research that suggests that administering European mistletoe extract might offer help in the treatment of: (9)
- Breast cancer — Limited studies have found that injections might help stop breast cancer tumor growth and increase lifespan.
- Advanced pancreatic cancer — Mistletoe extract might be able to help improve survival time by several months when injected into the tumor in people with pancreatic cancer.
- Colon cancer
- Bladder cancer (especially in those with reoccurring bladder cancer)
- Stomach cancer
- Liver cancer
- Lung cancer
- Ovarian cancer
- Uterine cancer
Another potential use is reducing side effects of cancer treatments, including chemotherapy and radiation therapy and improving quality of life during recovery. A 2016 systematic review published in the Journal of Complimentary and Alternative Medicine found that mistletoe therapy (MT) trials in cancer show “promising results in improvement of patients’ quality of life during chemotherapy and reduction of fatigue.”
Researchers carried out the review because patients’ side effects and tolerability have not been systematically reviewed. The review found that overall, patients reported “demonstrable changes to their physical, emotional and psychosocial well-being following MT, as well as a reduction in chemotherapy side effects.” However, the conclusion of the review was that “given the variation in context of MT delivery across the articles, it is not possible to ascribe changes in patients’ quality of life specifically to MT.”
2. May Support Cardiovascular Health
There’s some evidence that mistletoe, especially the species called L. ferrugineus and Loranthus micranthus (African mistletoe), have traditionally been used for hypertension and gastrointestinal complaint management. These types may lower the risk for blood vessel conditions, including high blood pressure and atherosclerosis (thickening and hardening of the arteries).
A 2011 study published in Biochemistry Research International that was conducted on rats found that it had anti-hypertensive, anti-artherogenic and vasorelaxation effects that could potentially reduce cardiac episodes. However, study results have been mixed overall. Some even suggest it may make heart disease worse in certain patients.
3. Used Topically to Manage Skin Conditions
Mistletoe can be used for bathing. You can also apply it to the skin to help treat varicose veins, ulcers on the lower legs and eczema. Some also believe that it has pain-killing properties and can be used to help treat joint pain (rheumatic and neuralgic pains) when it’s rubbed into the skin.
4. May Help Treat Depression and Anxiety
Mistletoes have emerged as promising alternative therapy against mood-related conditions including depression, anxiety and fatigue, especially when these conditions are associated with cancer treatments. Several studies have shown that mistletoe can improve coping ability of both cancer patients and survivors.
5. May Support Hormonal Balance
Mistletoe has been used to help manage menopause symptoms, such as fatigue and trouble sleeping, and to regulate hormones when a woman experiences irregular periods. In post-menopausal women, the population most likely to suffer from osteoporosis, it may also be able to help defend against weak bones and fractures.
6. Used to Fight Colds, Coughs and Asthma
Although not many studies have directly observed mistletoe’s effects on the respiratory system, various mistletoe plant species are claimed to exert antioxidant, analgesic, anti-inflammatory and immune-stimulatory properties, making them defenders against illnesses and infections. Supplementing with mistletoe might be able to help fight off common colds, sore throats, fevers, coughs and respiratory issues like asthma, although this hasn’t been proven in many studies. To defend against respiratory issues and colds, it can be consumed as a tea/tincture or inhaled.
What Are Mistletoe Injections?
The effectiveness of mistletoe injections depends on the exact type of extract being used. Products can vary considerably, since many factors affect the quality of the extract. These include the type of host tree, the exact species, how the extract is gathered and the time of year the plant is picked.
Extracts are made in water-based solutions (made with water and alcohol) that are commonly injected. Products are sometimes named according to the type of tree that the plant grows. As mentioned above, subcutaneous mistletoe injections (those administered below the skin) are only approved for use in clinical trials in the U.S at this time. Usually, injections are given under the skin. Sometimes they can be administered into a vein, pleural cavity or a tumor.
In countries other than the U.S., there are several brands of extracts/injections that are currently available by prescription, including: Iscador, Eurixor, Helixor, Isorel, Vysorel and ABNOBAviscum. While some in-vitro studies have demonstrated growth inhibition, cell death and anti-tumor activity in cancer patients using mistletoe extract, the consensus in the U.S. is that there still isn’t solid evidence for its effectiveness.
Uses in Traditional Medicine
The name “mistletoe” is believed to have been derived from the Celtic word for “all-heal.” Records tell us there were many historical uses of mistletoe, most of which focused on healing the nervous system. Mistletoe was used to treat conditions including: nervousness/anxiety (sometimes in combination with valerian root), convulsions, hysteria, neuralgia, skin problems, urinary disorders, fevers and heart disease.
In some traditional medicine systems, mistletoe was believed to be a natural “heart tonic” that could strengthen the force of the heartbeat and increase the heart rate. Herbal formulas that included mistletoe, valerian and vervain were often given for “all kinds of nervous complaints” caused by hormonal imbalances, fatigue, etc.
In traditional medicine systems, mistletoe was usually made into a healing tea or tincture. Another traditional use of mistletoe berries was using them to make salves for skin problems like sores and ulcers.
Mistletoe vs. Holly
- Like certain species of mistletoe, holly (Ilex aquifolium) is a plant also widely used for decoration around the Christmas holiday. These two plants are commonly used together, but they don’t look alike or have the same chemical properties.
- Just like with mistletoe, there are many species of holly. English holly, Oregon holly and American holly are used as ornamental Christmas greens. These types of holly plants are shrubs that have spiky, dark-green, thin, glossy leaves and red berries.
- The leaves of the holly species llex opaca, Ilex vomitoria and Ilex aquifolium are used to make medicine. Their berries are said to be “poisonous” because they can cause serious side effects if eaten.
- Holly has been used in traditional medicine for centuries. Some of the conditions that holly is said to help treat include: coughs, digestive disorders, jaundice, fevers, joint pain, swelling, water retention, heart disease and high blood pressure.
- Traditional uses of holly include consuming it as a heart tonic and digestive cleanser, since it has properties that can induce vomiting and change blood pressure.
Where to Find & How to Use
Mistletoe is usually sold as a dry herb. At home, dried mistletoe can be used to make teas and tinctures. It’s recommended that tea made from the mistletoe always be made as a cold infusion, since using very hot water may destroy some of the compounds found in mistletoe. For most people, the easiest way to make mistletoe tea will be with hot, but not boiling, water (like you could make green tea).
It’s also possible to take the extract by mouth. Depending on which country you live in, a doctor may prescribe extract injections.
Because products vary, always read directions carefully when purchasing mistletoe herb. Speak to your doctor if you take any medications, especially those for high blood pressure, since mistletoe does have a number of interactions with other drugs. Remember that mistletoe is capable of causing serious side effects, especially when you consume the leaves. The safest way to use mistletoe is under the care of an experienced herbalist or doctor. An herbalist might first test your reaction to a small dose by monitoring your pulse before and after. If your pulse begins to weaken and become more irregular, you know mistletoe is not a good herb for you to take.
- Use the smallest possible dose that exerts an obvious effect. Some herbalists use only one to two milliliters of extract per day in divided doses. Low doses of one milliliter per day are even used by some doctors as a complementary cancer treatment.
- Crude mistletoe fruit or herb used to make tea (typically to treat hypertension) is recommended at a dosage of 10 grams per day.
- Extracts are usually given by intravenous or subcutaneous injection at dosages of 0.1 to 30 milligrams, several times per week.
Mistletoe History and Facts
What’s the meaning of mistletoe? For example, Why do we kiss under the mistletoe?
Mistletoe has long been associated with peace, protection, romance and celebration. Today, the meaning of the mistletoe at Christmas is to serve as a sign of love and friendship.
When it comes to the meaning of “kissing under the mistletoe,” this holiday tradition is said to have first began with the Greek festival of Saturnalia. Other sources claim that this tradition started in England in churches. Records show that mistletoe first became a symbol of romance during the times of ancient Norse mythology, practiced by North Germanic/Scandinavian people in the 17th and 18th century. The custom of kissing beneath the mistletoe then spread to British servants and throughout England. Refusing to kiss someone beneath mistletoe was associated with bad luck, as were mistletoe plants that lost of their berries.
Historically mistletoe also symbolized the need to form a truce among enemies. The ancient Celts and Germans used European mistletoe as a ceremonial plant and believed that it had mystical powers. Mistletoe has long been a symbol of protection from misfortune, illness and violence as it “warded off evil spirits.” Historically, it’s also believed to have been a natural aphrodisiac and used to promote fertility.
- Mistletoe is a member of the Viscaceae plant family and is considered an evergreen hemiparasitic plant. Mistletoe is harvested for its berries, leaves and stems, which are used to make herbal extracts and medicines, including injections.
- There are more than 100 species that grow around the world. American mistletoe (Phoradendron flavescen) is the type that grows in the United States and is used as a romantic holiday decoration, while European mistletoe (Viscum album) is the species that has been used for centuries in traditional herbal medicine.
- Benefits include potentially helping against cancer, improving cardiovascular health, managing skin conditions, alleviating depression/anxiety, balancing hormones and fighting colds/fevers/respiratory issues.
- Injections are widely used in Europe to help with cancer. They aren’t yet approved in the U.S. due to a lack of reliable information from existing clinical trials.
- Is mistletoe poisonous or dangerous? While studies suggest it’s generally well-tolerated, products vary from brand to brand depending on many factors. Side effects like fever, chills, skin rash, diarrhea, headaches and allergic reactions are possible.
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