Drug & supplement interaction

Black Hellebore + Erythromycin

Erythromycin brand names: Erythro S, PCE, E-Mycin, Erythro-ES, EryPed Chewable, and others.

Moderate Interaction
Medically reviewed by · Updated September 2026
The bottom line Moderate

Black Hellebore has a moderate interaction with Erythromycin. Theoretically, concomitant use of macrolide antibiotics and black hellebore might increase risk of cardiac glycoside toxicity.

Read the full interaction report
SeverityModerate
LikelihoodPossible
EvidenceD
What do Severity, Likelihood & Evidence mean?
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Interaction report

Black Hellebore and Erythromycin

Here is the interaction we found between these two, with the evidence behind it.

Moderate

MACROLIDE ANTIBIOTICS

Why this applies to Erythromycin

Erythromycin falls under MACROLIDE ANTIBIOTICS — the group Black Hellebore interacts with.

Theoretically, concomitant use of macrolide antibiotics and black hellebore might increase risk of cardiac glycoside toxicity. Some of these drugs include erythromycin, azithromycin, and clarithromycin.
Severity Moderate Likelihood Possible Evidence D

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.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the short version: Black Hellebore is a genuinely toxic plant, not a safe supplement, and it contains compounds that act on your heart much like digoxin and other cardiac glycosides. Erythromycin is an antibiotic that can slightly raise blood levels of those heart-affecting compounds and may also nudge your heart's electrical rhythm (it can prolong the QT interval). Put the two together and, in theory, you could push toward a dangerous heart rhythm or signs of glycoside toxicity, such as nausea, vomiting, a slow or irregular pulse, dizziness, or vision changes.

I want to be honest that this concern is theoretical, based on how the two work rather than real-world reports. Still, Black Hellebore simply isn't something to take at all. Please run any product containing it past your doctor or pharmacist first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Ellenhorn MJ, et al. Ellenhorn's Medical Toxicology: Diagnoses and Treatment of Human Poisoning. 2nd ed. Baltimore, MD: Williams & Wilkins, 1997.

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction 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.
  • PossibleInteraction 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.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Black Hellebore Also Interacts With Other Medications

Black Hellebore has 132 moderate known drug interactions in our database — the Erythromycin one above is one of them. If you take anything else, check it against the full list below.

Moderate 132 No known interaction 2,698 (incl. Erythromycin)
Taking anything else?

Check Another of Your Medications Against Black Hellebore

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

From our Q&A

Questions About Black Hellebore or Erythromycin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Black Hellebore or Erythromycin, 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 Erythromycin

This page covers Black Hellebore only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Erythromycin page lists 204 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Beer (major) and Cesium (major).

By severity: 11 major · 153 moderate · 40 minor.

From our pharmacist’s overview on the Erythromycin page

“Erythromycin calls for more supplement caution than most antibiotics, and the reason is one liver enzyme, CYP3A4. Erythromycin both blocks that enzyme and is broken down by it, so grapefruit can push erythromycin levels up while St.”

Reviewed by 2 · Jul 18, 2026

Open the Erythromycin interaction page

One more smart check

Taking Black Hellebore as Part of a Dietary Supplement Product? Check It for Interactions

We hold 1 real supplement products containing Black Hellebore, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Black Hellebore. Your product may carry other ingredients that interact with Erythromycin too, on top of Black Hellebore — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Black Hellebore and Erythromycin 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 Black Hellebore
Top half

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

29 days ago today
Medication Erythromycin
Top 25%

#375 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.

Supplement

About Black Hellebore

What is Black Hellebore?

Black Hellebore
  • Constipation (historical purgative)
  • Mental and nervous disorders (historical)
  • Worm and parasite expulsion (historical)
  • Fluid retention (historical)
  • Heart conditions (historical, dangerous)

Black Hellebore is a highly toxic plant that was used in old folk medicine but has no proven, safe modern use. Because even small amounts can cause severe poisoning and dangerous heart rhythm problems, it should not be taken as a supplement. Talk to a doctor or pharmacist before considering any product that contains it.

Read the full Black Hellebore monograph & all interactions
Medication

About Erythromycin

What Is Erythromycin Used For?

Brand names: Erythro S, PCE, E-Mycin, Erythro-ES, EryPed Chewable, Eryc, Ery-Tab, Rythro Enca, Erythro E-C, Erythro Base, Ilosone, Ilotycin

Erythromycin treats bacterial infections caused by susceptible organisms. Oral and intravenous forms are used for upper and lower respiratory tract infections, skin and soft-tissue infections, pertussis (whooping cough), Legionnaires' disease, sexually transmitted infections (gonorrhea, syphilis, chlamydia), listeriosis, and other conditions. Erythrocin Lactobionate IV and erythromycin lactobionate injection are specifically for patients who cannot take oral medication or who need rapid, high blood levels due to severe infection — IV therapy should be switched to oral as soon as appropriate.

Erythromycin topical solution 2% and Ery 2% Pads (swabs) are indicated only for the topical treatment of acne vulgaris (acne) and are applied directly to the skin — they are not used for internal infections.

See full Erythromycin drug information
Keep checking

Other Drugs & Black Hellebore

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

0Major
132Moderate
0Minor
2,697No known interaction
132 Moderate 2,697 No interaction
Moderate

132 interactions

Showing 60 of 132 moderate interactions — see all 132 on the Black Hellebore page.

No interaction 2,697 drugs checked — show the list

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

Showing the 60 most looked-up of 2,697 medications checked with no known interaction — see the full Black Hellebore list.

See the full Black Hellebore interactions page
See every supplement checked against Erythromycin, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

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

Keep exploring
Black Hellebore monograph › Uses, safety, and every drug interaction in one place Erythromycin supplement interactions › Every supplement checked against Erythromycin, ranked by severity Erythromycin drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Black Hellebore and Erythromycin Together: Common Questions

Can you take Black Hellebore with Erythromycin?
There is a moderate interaction, so it may be acceptable with monitoring or timing changes — but check with your pharmacist first. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Black Hellebore and Erythromycin interaction?
We rate it Moderate. This combination may require monitoring, a dose adjustment, or separating the times you take each one. Consult your pharmacist before using them together.

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

Still Have a Question About Erythromycin and Black 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.