Drug & supplement interaction

American Hellebore + Nivolumab

Nivolumab brand name: Opdivo.

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 Nivolumab 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 Nivolumab 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 Nivolumab

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

Why No Interaction Is Listed for Nivolumab

Interactions in our licensed database are recorded against drug classes, not just single drug names. Nivolumab is filed under a single classification — antineoplastics. 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 Nivolumab’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 — Nivolumab 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. Nivolumab)
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 Nivolumab 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.

  • Trouble swallowing 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.

    Nivolumab

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

  • Low blood pressure 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.

    Nivolumab

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

  • Diarrhea / Vomiting / Nausea reported in 5.4% of FDA reports for Nivolumab 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.

    Nivolumab

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

  • Dizziness / Headache Additional detail

    American Hellebore

    Recorded for American Hellebore in the same Natural Medicines adverse-effect record shown under Low blood pressure above.

    Nivolumab

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

Reported for American Hellebore but not commonly for Nivolumab: seizures, a slow heartbeat and loss of vision.

Effects for Nivolumab 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 96,645 voluntary FDA FAERS reports for Nivolumab 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.

How to take them

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

At least one FDA label for a product containing Nivolumab 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 Nivolumab 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 Nivolumab 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.

Table 2: Recommended Dosages of Intravenous OPDIVO in Combination with Other Therapeutic Agents Indication Recommended OPDIVO Dosage Duration of Therapy Unresectable or metastatic melanoma 1 mg/kg every 3 weeks with ipilimumab 3 mg/kg In combination with ipilimumab for a maximum of 4 doses or until unacceptable toxicity, whichever occurs earlier Adult patients and pediatric patients aged 12 years

From the Dosage and Administration section of the FDA label we read for Nivolumab — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

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.

Everything else you take

See Every Supplement That Interacts With Nivolumab

This page covers American Hellebore only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Nivolumab page lists 1 supplement it has a documented interaction with, worst first, each one explained.

The most serious there right now: American Pawpaw (minor).

By severity: 1 minor.

From our pharmacist’s overview on the Nivolumab page

“Nivolumab (Opdivo) is an immunotherapy infusion that trains the body's own immune system to recognize and attack cancer cells, the kind of drug you might expect to carry a long list of supplement warnings. It does not.”

Reviewed by 2 · Jul 18, 2026

Open the Nivolumab interaction page

How much people look this up

Where American Hellebore and Nivolumab 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

#1,190 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Nivolumab
Steady interest

#2,042 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 Nivolumab 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 Nivolumab Injection

What Is Nivolumab Injection Used For?

Brand name: Opdivo

Opdivo (nivolumab) is used to treat many types of cancer in adults, and some in patients 12 years and older. It can be used alone or in combination with other therapies depending on the cancer type and stage. Cancers it treats include melanoma (including after surgery to reduce the chance of the cancer coming back), non-small cell lung cancer, malignant pleural mesothelioma, advanced renal cell carcinoma (kidney cancer), classical Hodgkin lymphoma, squamous cell carcinoma of the head and neck, urothelial carcinoma (bladder cancer), colorectal cancer with specific genetic features (MSI-H or dMMR), hepatocellular carcinoma (liver cancer), esophageal cancer, gastroesophageal junction cancer, and gastric (stomach) cancer.

Some uses require the tumor to test positive for a protein called PD-L1, and some are specific to certain stages of disease or prior treatments received. Your oncologist will determine which use applies to your situation.

Most-Reported Side Effects for Nivolumab

From FAERS, the FDA’s public side-effect reporting system (96,645 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Malignant neoplasm progression 9,878 reports
Diarrhea 5,251 reports
Fatigue 4,195 reports
Fever 3,721 reports
Nausea 3,182 reports
See full Nivolumab Injection 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 Nivolumab, 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 Nivolumab Together: Common Questions

Is it safe to take American Hellebore with Nivolumab?
We do not list a known interaction between American Hellebore and Nivolumab. 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 Nivolumab have any of the same side effects?
Yes — our sources link each of them separately to 7 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 Nivolumab at the same time of day?
At least one FDA label for a product containing Nivolumab 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 Nivolumab 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 Nivolumab combination checked?
Interactions in our licensed database are recorded against drug classes. Nivolumab is filed under 1 classification, and American Hellebore has documented interactions with 2 drug classes — none of Nivolumab'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 — Nivolumab 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 Nivolumab interact with any supplements?
Yes. Nivolumab has documented interactions with 1 supplement in our database — American Hellebore is not one of them. The Nivolumab 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 Nivolumab Injection drug information The full plain-English guide to this medication Nivolumab supplement interactions Every supplement checked against Nivolumab, 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 Nivolumab 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.