Drug & supplement interaction

Black Hellebore + Benzthiazide

Benzthiazide brand name: Exna.

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

Black Hellebore has a moderate interaction with Benzthiazide. Theoretically, concomitant use of potassium depleting diuretics and black hellebore can increase the risk of cardiac glycoside toxicity due to potassium depletion.

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

Black Hellebore and Benzthiazide

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

Moderate

DIURETIC DRUGS

Why this applies to Benzthiazide

Benzthiazide falls under DIURETIC DRUGS — the group Black Hellebore interacts with.

Theoretically, concomitant use of potassium depleting diuretics and black hellebore can increase the risk of cardiac glycoside toxicity due to potassium depletion. Some diuretics that can deplete potassium include chlorothiazide (Diuril), chlorthalidone (Thalitone), furosemide (Lasix), hydrochlorothiazide (HCTZ, Hydrodiuril, Microzide), and others.
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

First, the big picture: Black Hellebore is a genuinely poisonous plant, not a safe supplement, so I'd steer clear of it entirely. But here's the specific concern when you pair it with Benzthiazide (Exna). Benzthiazide is a thiazide-type water pill, and one of its everyday effects is flushing potassium out of your body through your urine. Low potassium on its own can leave you feeling weak, crampy, or with an irregular heartbeat.

Black Hellebore contains compounds that act on the heart much like digoxin-type chemicals. When potassium runs low, the heart becomes more sensitive to those compounds, which raises the risk of dangerous heart rhythm problems. This warning is theoretical, based on how the two work, but the stakes are high. Please don't combine them, and check with your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Burnham TH, ed. Drug Facts and Comparisons, Updated Monthly. Facts and Comparisons, St. Louis, MO.

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 Benzthiazide 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. Benzthiazide)
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.

Everything else you take

See Every Supplement That Interacts With Benzthiazide

This page covers Black Hellebore only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Benzthiazide page lists 227 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Asarabacca (major) and Dolomite (major).

By severity: 10 major · 192 moderate · 25 minor.

From our pharmacist’s overview on the Benzthiazide page

“Benzthiazide (Exna), a thiazide water pill prescribed for high blood pressure and fluid retention, comes with a supplement list I would treat with genuine respect. Most of what appears here either drops blood pressure further than intended or deepens the potassium and fluid loss the drug already causes, and a handful can strain the kid…”

Reviewed by 2 · Jul 18, 2026

Open the Benzthiazide 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 Benzthiazide 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 Benzthiazide 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 Benzthiazide
Top half

#1,136 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
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 Benzthiazide, 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 Benzthiazide supplement interactions › Every supplement checked against Benzthiazide, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Black Hellebore and Benzthiazide Together: Common Questions

Can you take Black Hellebore with Benzthiazide?
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 Benzthiazide 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 Benzthiazide 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.