Drug & supplement interaction

American Hellebore + Promethazine

Promethazine brand name: Phenergan.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between American Hellebore and Promethazine 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 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 Promethazine

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 Promethazine 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 Promethazine and American Hellebore? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Promethazine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Promethazine is filed under 4 classifications — including phenothiazines, anticholinergic drugs, photosensitizing 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 Promethazine’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 — Promethazine 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. Promethazine)
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 Promethazine 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. 2 of them are worth acting on rather than waiting out — marked below.

  • A slow heartbeat Worth acting on Additional detail

    American Hellebore

    “Orally, American hellebore can cause arrhythmias, bradycardia, hypotension, heart block, and even death due to cardiac arrest or asphyxiation (17,18,13435,31101,31105,31110,31118,31123,31131,31132).”

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

    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.

    Promethazine

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

  • 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.

    Promethazine

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

  • Vomiting / Nausea reported in 11.7% of FDA reports for Promethazine 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.

    Promethazine

    Listed in the ADVERSE REACTIONS section of the FDA label for Promethazine, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Dizziness Additional detail

    American Hellebore

    Recorded for American Hellebore in the same Natural Medicines adverse-effect record shown under A slow heartbeat above.

    Promethazine

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

Reported for American Hellebore but not commonly for Promethazine: low blood pressure, trouble swallowing, loss of vision and diarrhea.

Effects for Promethazine come from the ADVERSE REACTIONS section of its FDA label; effects for American Hellebore come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 22,361 voluntary FDA FAERS reports for Promethazine that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

From our Q&A

Questions About American Hellebore or Promethazine

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 Promethazine, 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 Promethazine

This page covers American Hellebore only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Promethazine page lists 83 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Henbane (major), Scopolia (major), Alfalfa (moderate) and Angel's Trumpet (moderate).

By severity: 3 major · 57 moderate · 23 minor.

From our pharmacist’s overview on the Promethazine page

“Promethazine (Phenergan) is a phenothiazine antihistamine used for allergies, nausea, and motion sickness, and it is strongly anticholinergic on its own, causing dry mouth, blurred vision, drowsiness, and constipation. That is why the 83 supplements and herbs on this list deserve real attention, starting with the three rated major.”

Reviewed by 2 · Jul 18, 2026

Open the Promethazine interaction page

How much people look this up

Where American Hellebore and Promethazine 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
Top half

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

29 days ago today
Medication Promethazine
Top half

#1,214 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 20, 2026. The American Hellebore and Promethazine 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 Promethazine

What Is Promethazine Used For?

Brand name: Phenergan

Promethazine is used for a wide range of conditions. Tablets, oral solution, and rectal suppositories (brands including Phenergan, Promethegan, and Phenadoz) are approved for seasonal and perennial allergic rhinitis, vasomotor rhinitis, allergic conjunctivitis, hives (urticaria), angioedema, dermographism, and allergic reactions to blood or plasma. They are also used for motion sickness (both prevention and active treatment), nausea and vomiting related to anesthesia and surgery, sedation, and as a helper medication alongside pain relievers after surgery.

Promethazine hydrochloride injection (brands including Phenergan and Promethazine HCl injection) is used for many of the same purposes but is reserved for situations where oral treatment is not possible — including allergic emergencies as an adjunct to epinephrine, sedation during labor, and as an aid during certain surgical procedures such as bronchoscopy and eye surgery.

Most-Reported Side Effects for Promethazine

From FAERS, the FDA’s public side-effect reporting system (22,614 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Dependence 3,586 reports
Nausea 2,646 reports
Vomiting 1,802 reports
Fatigue 1,496 reports
Diarrhea 1,341 reports
See full Promethazine 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 Promethazine, 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 Promethazine Together: Common Questions

Is it safe to take American Hellebore with Promethazine?
We do not list a known interaction between American Hellebore and Promethazine. 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 Promethazine 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.
How was the American Hellebore and Promethazine combination checked?
Interactions in our licensed database are recorded against drug classes. Promethazine is filed under 4 classifications, and American Hellebore has documented interactions with 2 drug classes — none of Promethazine'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 — Promethazine 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 Promethazine interact with any supplements?
Yes. Promethazine has documented interactions with 83 supplements in our database — American Hellebore is not one of them. The Promethazine 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 Promethazine drug information The full plain-English guide to this medication Promethazine supplement interactions Every supplement checked against Promethazine, 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 Promethazine 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.