Drug & supplement interaction

American Hellebore + Levothyroxine

Levothyroxine brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, and others.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between American Hellebore and Levothyroxine in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Levothyroxine states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

American Hellebore and Levothyroxine

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Levothyroxine and American Hellebore in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

American Hellebore safety at a glance

American Hellebore overall Avoid The plant is highly toxic and can cause life-threatening poisoning even at low doses.
Pregnancy Avoid Toxic alkaloids may harm the parent and fetus; do not use.
Breastfeeding Avoid Safety is unknown and the plant is poisonous; avoid use.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Levothyroxine and American Hellebore? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Levothyroxine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Levothyroxine is filed under 3 classifications — including thyroid hormone, oral drugs. American Hellebore has documented interactions with 2 drug classes — the most serious being antihypertensive drugs (major) and qt interval-prolonging drugs (major) — and none of Levothyroxine’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

American Hellebore Does Interact With Other Medications

American Hellebore has 328 major, known drug interactions in our database — Levothyroxine isn’t one of them. If you take anything else, check it against the full list below.

Major 328 No known interaction 2,502 (incl. Levothyroxine)
Taking anything else?

Check Another of Your Medications Against American Hellebore

Covers the 2,830 medications we’ve checked against American Hellebore. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests American Hellebore and Levothyroxine May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. One of them is worth acting on rather than waiting out — marked below.

  • Seizures Worth acting on Additional detail

    American Hellebore

    “Orally, American hellebore can cause depressed mental status, headache, lacrimation, salivation, dysphagia, paresthesias, vertigo, blindness, paralysis, and mild convulsions (17,18,13435,31101,31105,31110,31118,31123,31131,31132).”

    American Hellebore · Natural Medicines adverse-effect record, reported in cluster headache.

    6 sources cited
    1. 17. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    3. 13435. Zagler B, Zelger A, Salvatore C, et al. Dietary poisoning with Veratrum album--a report of two cases. Wien Klin Wochenschr 2005;117:106-8. PubMed
    4. 31101. Prince, L. A. and Stork, C. M. Prolonged cardiotoxicity from poison lilly (Veratrum viride). Vet.Hum.Toxicol. 2000;42(5):282-285.
    5. 31105. ZUMOFF, B. Temporary atrioventricular conduction disturbance associated with ingestion of Veratrum viride. Am Heart J 1954;47(4):630-633. PubMed
    6. 31110. BRONSKY, D., BERNSTEIN, M., and CHESROW, E. J. Cardiac arrhythmia from Veratrum viride. Geriatrics 1957;12(6):389-393.

    Levothyroxine

    Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed ›

  • Diarrhea / Vomiting / Nausea Additional detail

    American Hellebore

    “Orally, American hellebore can cause burning sensations of the mouth and pharynx, diarrhea, nausea, and vomiting (17,18,13435,31101,31105,31110,31118,31123,31131,31132).”

    American Hellebore · Natural Medicines adverse-effect record, reported in diarrhea.

    6 sources cited
    1. 17. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
    3. 13435. Zagler B, Zelger A, Salvatore C, et al. Dietary poisoning with Veratrum album--a report of two cases. Wien Klin Wochenschr 2005;117:106-8. PubMed
    4. 31101. Prince, L. A. and Stork, C. M. Prolonged cardiotoxicity from poison lilly (Veratrum viride). Vet.Hum.Toxicol. 2000;42(5):282-285.
    5. 31105. ZUMOFF, B. Temporary atrioventricular conduction disturbance associated with ingestion of Veratrum viride. Am Heart J 1954;47(4):630-633. PubMed
    6. 31110. BRONSKY, D., BERNSTEIN, M., and CHESROW, E. J. Cardiac arrhythmia from Veratrum viride. Geriatrics 1957;12(6):389-393.

    Levothyroxine

    Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed ›

  • Headache Additional detail

    American Hellebore

    Recorded for American Hellebore in the same Natural Medicines adverse-effect record shown under Diarrhea / Vomiting / Nausea above.

    Levothyroxine

    Listed in the ADVERSE REACTIONS section of the FDA label for Levothyroxine. Read the label on DailyMed ›

Reported for American Hellebore but not commonly for Levothyroxine: a slow heartbeat, low blood pressure, trouble swallowing and loss of vision.

Effects for Levothyroxine come from the ADVERSE REACTIONS section of its FDA label; effects for American Hellebore come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Levothyroxine Products Have a Food Rule — American Hellebore Should Not Break It

At least one FDA label for a product containing Levothyroxine says to take it on an empty stomach. Most supplements — American Hellebore included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Levothyroxine on its own and move American Hellebore to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Levothyroxine products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

From our Q&A

Questions About American Hellebore or Levothyroxine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers American Hellebore or Levothyroxine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Levothyroxine

This page covers American Hellebore only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Levothyroxine page lists 50 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Tiratricol (major), Acetyl-l-carnitine (moderate), Alpha-lipoic Acid (moderate) and Ascophyllum Nodosum (moderate).

By severity: 2 major · 39 moderate · 9 minor.

From our pharmacist’s overview on the Levothyroxine page

“Levothyroxine replaces a hormone your body measures in tiny amounts, so small shifts in its blood level show up in how you feel, and I treat this list with genuine care. Nearly everything on it does one of two things: blocks the pill from being absorbed in the gut, the way everyday minerals like calcium do by binding it into complexes,…”

Reviewed by 2 · Jul 18, 2026

Open the Levothyroxine interaction page

How much people look this up

Where American Hellebore and Levothyroxine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement American Hellebore
Steady interest

#886 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Levothyroxine
Top 10

#2 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every American Hellebore reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The American Hellebore and Levothyroxine records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About American Hellebore

What is American Hellebore?

American Hellebore
  • High blood pressure
  • Slowing heart rate
  • Toxemia of pregnancy (historical)
  • Convulsions (historical)
  • Pain relief (traditional)

American Hellebore (Veratrum viride) is a highly poisonous plant whose root contains toxic alkaloids that can cause dangerous drops in heart rate and blood pressure, even in small amounts. It is not a safe self-care supplement, and any non-homeopathic product carries a serious risk of poisoning. Do not use it without medical supervision, and talk to a pharmacist or doctor before considering any product that contains it.

Veratrum viride · Melanthiaceae · Rhizome and root · Homeopathic preparations (highly diluted); historically tinctures

An interaction check asks whether these two react with each other — it does not ask whether American Hellebore is a good idea for someone in your situation. Here is what our American Hellebore record says about it on its own.

American Hellebore: dosing

There is no established safe dose of American Hellebore for self-care. Historically it was given only by trained practitioners using carefully measured tinctures, and even then poisonings occurred.The only products generally found today are homeopathic, which are extremely diluted. Never make or take a preparation from the raw plant.

From our American Hellebore monograph — the full record covers uses, side effects and every documented interaction.

Read the full American Hellebore monograph & all interactions
Medication

About Levothyroxine

What Is Levothyroxine Used For?

Brand names: Euthyrox, Levothroid, Unithroid, Synthroid, Levoxyl, Levo-T, Eltroxin, Estre, Levothyroxine, Novothyrox, Levolet

Levothyroxine replaces or supplements the thyroid hormone your body isn't making enough of. It's used for hypothyroidism — an underactive thyroid — in adults, children, and even newborns, whether the cause is the thyroid gland itself, the pituitary gland, or the hypothalamus in the brain.

It's also used alongside surgery and radioiodine treatment in people with certain types of thyroid cancer, to help suppress the hormone that can stimulate cancer growth. It is not meant for weight loss, treating benign thyroid nodules in people who have enough iodine, or for hypothyroidism during recovery from a temporary condition called subacute thyroiditis.

See full Levothyroxine drug information
Keep checking

Other Drugs & American Hellebore

Browse every other medication we’ve checked against American Hellebore — both the ones with a known interaction and the ones without. Select any drug for the full detail.

328Major
0Moderate
0Minor
2,501No known interaction
328 Major 2,501 No interaction
Major

328 interactions

Showing 60 of 328 major interactions — see all 328 on the American Hellebore page.

No interaction 2,501 drugs checked — show the list

We also checked American Hellebore against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,501 medications checked with no known interaction — see the full American Hellebore list.

See the full American Hellebore interactions page
See every supplement checked against Levothyroxine, ranked by severity
Evidence & sources

American Hellebore References

The 15 references that drive our American Hellebore 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. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Zagler B, Zelger A, Salvatore C, et al. Dietary poisoning with Veratrum album--a report of two cases. Wien Klin Wochenschr 2005;117:106-8. PubMed
  4. Prince, L. A. and Stork, C. M. Prolonged cardiotoxicity from poison lilly (Veratrum viride). Vet.Hum.Toxicol. 2000;42(5):282-285.
  5. ZUMOFF, B. Temporary atrioventricular conduction disturbance associated with ingestion of Veratrum viride. Am Heart J 1954;47(4):630-633. PubMed
  6. BRONSKY, D., BERNSTEIN, M., and CHESROW, E. J. Cardiac arrhythmia from Veratrum viride. Geriatrics 1957;12(6):389-393.
  7. GOURZIS, J. and BAUER, R. O. Chronic toxicity of a purified extract of Veratrum viride. Proc.Soc.Exp Biol Med 1951;76(4):767-770. DOI
  8. NEWMAN, A. J. Intoxication with Veratrum viride. J Pediatr 1952;40(2):233-234. PubMed
  9. Assali, N. S., Brust, A. A., Garber, S. T., and Ferris, E. B. COMPARATIVE STUDY OF THE EFFECTS OF TETRAETHYL-AMMONIUM CHLORIDE AND VERATRUM VIRIDE ON BLOOD PRESSURE IN NORMAL AND TOXEMIC PREGNANCY. J Clin Invest 1950;29(3):290-296. PubMed
  10. Jaffe, A. M., Gephardt, D., and Courtemanche, L. Poisoning due to ingestion of Veratrum viride (false hellebore). J.Emerg.Med. 1990;8(2):161-167. PubMed
  11. Komchatov, IuN and Nasirov, G. S. [Poisoning by a tincture of false hellebore]. Sud.Med.Ekspert. 1988;31(1):51-52.
  12. Crummett, D., Bronstein, D., and Weaver, Z., III. Accidental Veratrum viride poisoning in three "ramp" foragers. N.C.Med.J. 1985;46(9):469-471.
  13. Garnier, R., Carlier, P., Hoffelt, J., and Savidan, A. [Acute dietary poisoning by white hellebore (Veratrum album L.). Clinical and analytical data. A propos of 5 cases]. Ann.Med.Interne (Paris) 1985;136(2):125-128.
  14. Bechtel LK, Lawrence DT, Haverstick D, et al. Ingestion of false hellebore plants can cross-react with a digoxin clinical chemistry assay. Clin Toxicol (Phila). 2010;48(5):435-42. PubMed
  15. Forrester JD, Price JH, Holstege CP. Intoxication with a ramp (Allium tricocca) mimicker. False hellebore (Veratrum viride) ingestion. Wilderness Environ Med. 2010;21(1):61-3.

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking American Hellebore and Levothyroxine Together: Common Questions

Is it safe to take American Hellebore with Levothyroxine?
We do not list a known interaction between American Hellebore and Levothyroxine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do American Hellebore and Levothyroxine have any of the same side effects?
Yes — our sources link each of them separately to 5 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take American Hellebore and Levothyroxine at the same time of day?
At least one FDA label for a product containing Levothyroxine says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Levothyroxine on its own and move American Hellebore to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
How was the American Hellebore and Levothyroxine combination checked?
Interactions in our licensed database are recorded against drug classes. Levothyroxine is filed under 3 classifications, and American Hellebore has documented interactions with 2 drug classes — none of Levothyroxine's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does American Hellebore interact with any other medications?
Yes. American Hellebore has 328 documented drug interactions in our database — Levothyroxine is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Levothyroxine interact with any supplements?
Yes. Levothyroxine has documented interactions with 50 supplements in our database — American Hellebore is not one of them. The Levothyroxine interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

American Hellebore monograph Uses, safety profile, and every drug interaction in one place Levothyroxine drug information The full plain-English guide to this medication Levothyroxine supplement interactions Every supplement checked against Levothyroxine, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 15 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Levothyroxine and American Hellebore?

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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.