Herb & supplement monograph

American Mistletoe Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by ·Updated July 2026
What is this page for?

First and foremost: how American Mistletoe interacts with medications. The heart of this page is the interaction list — every drug American Mistletoe is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what American Mistletoe is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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American Mistletoe Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

American Mistletoe drug interactions are a serious concern, because every interaction on record is rated major and centers on the heart and blood vessels. All of the many listed interactions carry a major severity rating, backed by human case reports rather than lab theory alone.

Interactions deserving the most attention

The biggest concerns are antihypertensive drugs (blood pressure medications) and vasodilators such as hydralazine. American mistletoe contains phoratoxin, a compound that is toxic to humans and can tighten blood vessels, raising blood pressure and heart rate. This can work directly against medicines meant to lower blood pressure or relax blood vessels, and cases of heart toxicity have been reported. People with any heart condition should avoid this plant entirely.

What the rest of the list means

The long list of interacting medications largely reflects the many different drugs used to treat blood pressure and circulation, all affected by the same mechanism. Unlike many supplements whose interactions are mostly theoretical, this one is grounded in documented human harm. It is worth knowing that American mistletoe is uncommon in dietary supplements, so exposure through products on the shelf is rare.

Check your medications against American Mistletoe

Based on HelloPharmacist’s American Mistletoe interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with American Mistletoe

190 medications have a known interaction with American Mistletoe, graded by severity. Select any drug for the full evidence-based detail.

190 major interactions. These combinations can be clinically significant — best avoided, or used only with close professional supervision. Always check with your pharmacist before combining them with American Mistletoe.

2,830 drugs
AcebutololRhotral, Sectral› AcetazolamideAk-Zol, Diamox› AliskirenTekturna› AmbrisentanLetairis, Volibris› AmilorideAmilamont, Midamor› Amiloride, HydrochlorothiazideAmil-Co, Amilzide, Moduret 25, Moduretic› AmlodipineNorliqva› Amlodipine BenzoateKaterzia› Amlodipine BesilateIstin› Amlodipine BesylateNorvasc› Amlodipine Besylate, BenazeprilLotrel› Amlodipine, CelecoxibConsensi› Ammonium ChlorideAmmonium Chloride› AprocitentanTryvio› AtenololAtenix, Tenormin› Atenolol, ChlortalidoneAtenixCo, Tenoret 50, Totaretic› Atenolol, ChlorthalidoneTenoretic› AvanafilStendra› AzilsartanEdarbi› Azilsartan, ChlorthalidoneEdarbyclor› BenazeprilLotensin› Benazepril, HydrochlorothiazideLotensin HCT› BendroflumethiazideAprinox, Naturetin, Neo-NaClex› Bendroflumethiazide, NadololCorzide› Bendroflumethiazide, Rauwolfia SerpentinaRauzide› BenzthiazideExna› BetaxololBetoptic, Kerlone› BisoprololZebeta› Bisoprolol, HydrochlorothiazideZiac› BosentanTracleer›
Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

  • Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
  • Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
  • Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
  • No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

  • Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
  • Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
  • Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

  • Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
  • Each drug listed above links to the full report for that exact American Mistletoe combination — clinical detail, likelihood, evidence level, and citations.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
The big picture

The kinds of drugs American Mistletoe affects

Every type of medication (drug category) American Mistletoe is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 2 drug categories American Mistletoe interacts with
Antihypertensive DrugsVasodilators
Antihypertensive Drugs

American mistletoe contains phoratoxin, a compound toxic to humans that induces smooth muscle contraction and vasoconstriction, potentially increasing blood pressure and heart rate. Case reports of cardiotoxicity have been documented with American mistletoe, and it should not be used with antihypertensive drugs or by individuals with cardiac conditions. American mistletoe is uncommon in dietary supplements, and formulations containing it are generally homeopathic. European mistletoe, which lacks phoratoxin, is more commonly used.

Likelihood Probable Evidence C
Vasodilators

American mistletoe contains phoratoxin, a compound toxic to humans that induces smooth muscle contraction and vasoconstriction, potentially increasing blood pressure and heart rate. Taking dietary supplements containing American mistletoe may counteract the effects of vasodilator drugs, such as hydralazine. It is important to note that American mistletoe is uncommon in dietary supplements. More commonly, European mistletoe is used as it does not contain phoratoxin.

Likelihood Probable Evidence C
Monograph

American Mistletoe: Uses, Safety & Side Effects

Medically reviewed by · Reviewed July 2026 ·
The bottom line

American mistletoe is a parasitic plant that is best known as a holiday decoration, not a proven medicine. It contains toxins that can harm the heart, gut, and blood vessels, and it has little reliable evidence to support any health use. We do not recommend taking it, and all parts should be kept away from children and pets.

American Mistletoe
Scientific name
Phoradendron leucarpum
Family
Santalaceae
Part used
Leaves, stems, and berries
Common forms
Rarely used as a supplement; historically as tea or dried plant. Most often seen as a holiday decoration.
People commonly use it for
  • Traditional folk remedies
  • Digestive complaints
  • Decorative holiday plant

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance
OverallBest avoided

American mistletoe contains toxic compounds and is not recommended for medicinal use.

PregnancyLikely Unsafe

When used orally. American mistletoe is considered an abortifacient.

Read the full pregnancy detail
BreastfeedingLikely Unsafe

When used orally; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

American mistletoe (Phoradendron leucarpum), also called Eastern mistletoe, is a parasitic plant that grows on hardwood trees such as oaks and hickories in the eastern United States and Mexico. It attaches to a host tree and draws water and nutrients from it.

Many people recognize mistletoe as a decoration hung during the winter holidays. Although some Native American traditions used the plant, it is rarely sold as a dietary supplement today. It is important to know that American mistletoe is not the same as European mistletoe (Viscum album), which is the type studied more often in research, especially in some cancer-care settings.

How it works

American mistletoe contains compounds called phoratoxins. In laboratory and animal studies, these toxins can cause smooth muscle to contract, which may increase activity in the uterus and intestines. They can also affect blood vessels and the heart, changing blood pressure and heart rate.

These effects are why the plant is considered toxic rather than helpful. Most of what is known comes from poisoning case reports and laboratory work, not from carefully designed human studies that show a health benefit.

Effectiveness

Does American Mistletoe work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by .

Evidence overview · 4 uses evaluated
4 Insufficient evidence
How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.
2Likely EffectiveGood evidence, though not yet conclusive.
3Possibly EffectiveSome evidence suggests a benefit.
4Possibly IneffectiveSome evidence it may not help.
5Likely IneffectiveFairly strong evidence it doesn’t help.
6IneffectiveStrong evidence it doesn’t work.
7Insufficient Reliable Evidence to RateToo little research to say either way.

For American Mistletoe, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 4 conditions — evidence insufficient to rate
Insufficient Reliable Evidence To Rate Abortion
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral American mistletoe for abortion, there is insufficient reliable information about the clinical effects of American mistletoe for this purpose.

Insufficient Reliable Evidence To Rate Constipation
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral American mistletoe for constipation, there is insufficient reliable information about the clinical effects of American mistletoe for this purpose.

Insufficient Reliable Evidence To Rate Gastroparesis
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral American mistletoe for gastroparesis, there is insufficient reliable information about the clinical effects of American mistletoe for this purpose.

Insufficient Reliable Evidence To Rate Hypotension
Rating & evidence shown verbatim from Natural Medicines

Although there has been interest in using oral American mistletoe for hypotension, there is insufficient reliable information about the clinical effects of American mistletoe for this purpose.

Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.

Safety & precautions

American mistletoe is considered a poisonous plant, and we do not recommend using it as a supplement. All parts, including the berries and leaves, can be harmful if swallowed in larger amounts. Keep it away from children and pets, especially during the holidays when decorative mistletoe is in the home.

Pregnancy: Avoid it. The plant may trigger uterine contractions and is toxic, which could be dangerous. Breastfeeding: Avoid it, since its safety is unknown and the plant is toxic.

If you or someone you know swallows mistletoe and feels unwell, contact Poison Control or seek medical care right away. Always talk with a pharmacist or doctor before using any mistletoe product.

Side effects

Eating American mistletoe can cause stomach upset, nausea, vomiting, diarrhea, and cramping. Larger amounts or strong preparations like teas may cause more serious problems.

Rare but serious effects can include changes in blood pressure and heart rate. There are case reports of death from cardiovascular collapse after drinking tea made from mistletoe berries. Because of these risks, this plant should not be taken for its supposed health benefits.

American Mistletoe: Reported Adverse Effects

Documented safety reports on American Mistletoe from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

Evidence on adverse effects related to American mistletoe is limited to retrospective case reviews from poison control centers. Most reports suggest that American mistletoe may be relatively well tolerated at lower doses. However, some reports suggest that American mistletoe can be severely toxic at high doses involving more than 20 berries or more than 5 leaves.

Most Common Adverse Effects:

Orally: Diarrhea, nausea, vomiting.

Serious Adverse Effects (Rare):

Orally: Bradycardia, cardiac arrest, death, delirium, hallucinations, hypertension.

Reports by condition
Cardiac arrest Cardiovascular

Orally, large doses of American mistletoe may cause bradycardia, hypertension, and cardiac arrest.

  1. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  2. Moore HW. Mistletoe poisoning: a review of the available literature, and the report of a case of probable fatal poisoning. J S Carolina Med Assoc 1963;59(8):269-271.
Delirium Psychiatric

Orally, large doses of American mistletoe may cause delirium and hallucinations.

  1. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
Diarrhea Gastrointestinal

Orally, American mistletoe can cause acute gastroenteritis. Consuming large doses of American mistletoe may cause nausea, vomiting, and diarrhea. Diarrhea and vomiting from ingestion of American mistletoe can lead to dehydration, hypovolemic shock, and cardiovascular collapse.

  1. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

Dosing

There is no established safe or effective dose of American mistletoe. Because the plant is toxic and not recommended for medicinal use, no dosing guidance can be given.

If you ever see a product containing mistletoe, do not take it without first speaking to a pharmacist or doctor. The safest approach is to avoid using American mistletoe internally altogether.

Pregnancy & Breastfeeding

American Mistletoe & Pregnancy

Likely Unsafe

When used orally. American mistletoe is considered an abortifacient.

  1. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.

American Mistletoe & Breastfeeding

Likely Unsafe

When used orally; avoid using.

  1. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  2. Foster S, Tyler VE. Tyler's Honest Herbal, 4th ed., Binghamton, NY: Haworth Herbal Press, 1999.
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

© 2026 Therapeutic Research Center

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

The 4 references that drive our American Mistletoe monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Foster S, Tyler VE. Tyler's Honest Herbal, 4th ed., Binghamton, NY: Haworth Herbal Press, 1999. DOI
  4. Moore HW. Mistletoe poisoning: a review of the available literature, and the report of a case of probable fatal poisoning. J S Carolina Med Assoc 1963;59(8):269-271.
Keep reading

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Pharmacist Counseling Corner

American Mistletoe: Common Questions

What is American Mistletoe used for, and does it work?
People use American Mistletoe for a range of reasons, but according to the Natural Medicines database the current clinical evidence is insufficient to confirm it works for the specific conditions it has been studied for. See the graded list on this page, and talk to your pharmacist or doctor before relying on it for any condition.
Does American Mistletoe interact with prescription medications?
Yes. We list 190 medications with a known interaction with American Mistletoe, including 190 rated major. Use the checker above to see how American Mistletoe interacts with a specific drug.
How are American Mistletoe interactions rated?
Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.
Is it safe to take American Mistletoe with my medications?
It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.
Where does this American Mistletoe interaction information come from?
Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.
Is American Mistletoe safe to eat?
No. It contains toxic compounds and can cause stomach upset, and in serious cases, dangerous changes in blood pressure and heart rate. Keep it away from children and pets.
Is American Mistletoe the same as the mistletoe used in cancer research?
No. Most cancer-related research uses European mistletoe (Viscum album), which is a different plant. American Mistletoe (Phoradendron leucarpum) has not been shown to be safe or effective.
What should I do if my child or pet swallows mistletoe?
Contact Poison Control or your doctor or veterinarian right away, especially if there are symptoms like vomiting, weakness, or changes in heart rate.
Can I use American Mistletoe while pregnant or breastfeeding?
No. It may cause uterine contractions and is toxic, so it should be avoided during pregnancy and breastfeeding.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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