Drug & supplement interaction

Foxglove + Clarithromycin

Clarithromycin brand names: Biaxin, Biaxin XL.

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

Foxglove has a moderate interaction with Clarithromycin. Theoretically, concomitant use of macrolide antibiotics increases the 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

Foxglove and Clarithromycin

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

Moderate

MACROLIDE ANTIBIOTICS

Why this applies to Clarithromycin

Clarithromycin falls under MACROLIDE ANTIBIOTICS — the group Foxglove interacts with.

Theoretically, concomitant use of macrolide antibiotics increases the risk of cardiac glycoside toxicity.
Foxglove contains varied cardiac glycosides, including digoxin. Macrolide antibiotics can the reduce elimination of some cardiac glycosides.
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, an important safety note: foxglove is a poisonous plant and should never be taken as a supplement. It naturally contains heart-affecting compounds called cardiac glycosides (the same family as the prescription drug digoxin). Even small amounts can throw off your heart rhythm.

Here's the concern when you pair it with clarithromycin: this antibiotic can slow down how your body clears those glycosides, so they can build up to dangerous levels. That can lead to cardiac glycoside toxicity, with signs like nausea, vomiting, blurred or yellow-tinted vision, confusion, and a slow or irregular heartbeat. This is based on how these drugs behave (theoretical) rather than lots of patient studies, but the risk is serious enough to respect. Please don't combine them, and check with your pharmacist or doctor.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  2. 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

Foxglove Also Interacts With Other Medications

Foxglove has 3 major, 129 moderate known drug interactions in our database — the Clarithromycin one above is one of them. If you take anything else, check it against the full list below.

Major 3 Moderate 129 No known interaction 2,698 (incl. Clarithromycin)
Taking anything else?

Check Another of Your Medications Against Foxglove

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

From our Q&A

Questions About Foxglove or Clarithromycin

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

This page covers Foxglove only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Clarithromycin page lists 196 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), Cesium (major) and Ephedra (major).

By severity: 9 major · 146 moderate · 41 minor.

Open the Clarithromycin interaction page

One more smart check

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

We hold 1 real supplement products containing Foxglove, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Foxglove. Your product may carry other ingredients that interact with Clarithromycin too, on top of Foxglove — 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 Foxglove and Clarithromycin 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 Foxglove
Top half

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

29 days ago today
Medication Clarithromycin
Top 25%

#438 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 Foxglove

What is Foxglove?

  • Heart failure (historical/medical use)
  • Irregular heartbeat (historical/medical use)
  • Fluid retention or 'dropsy' (historical use)
  • Ornamental garden plant

Foxglove is a beautiful but highly poisonous plant that contains powerful heart-affecting compounds called cardiac glycosides. It should never be used as a home remedy or supplement because even small amounts can cause life-threatening heart problems. The purified prescription drugs derived from it (like digoxin) are used only under close medical supervision.

Read the full Foxglove monograph & all interactions
Medication

About Clarithromycin

What Is Clarithromycin Used For?

Brand names: Biaxin, Biaxin XL

Clarithromycin tablets and oral suspension treat a range of mild to moderate bacterial infections in adults and children, including community-acquired pneumonia, acute sinus infections, acute bacterial flare-ups of chronic bronchitis, strep throat and tonsillitis, uncomplicated skin infections, and middle ear infections in children. Tablets are also used in adults to eliminate H. pylori bacteria (in combination with other medicines) to reduce the risk of duodenal ulcer recurrence.

Clarithromycin tablets — but not the extended-release tablet — are also used to treat and prevent disseminated Mycobacterium avium complex (MAC) infections in people with advanced HIV. Clarithromycin extended-release tablets are approved only for acute bacterial exacerbation of chronic bronchitis, acute maxillary sinusitis, and community-acquired pneumonia in adults — not for the other conditions listed above.

See full Clarithromycin drug information
Keep checking

Other Drugs & Foxglove

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

3Major
129Moderate
0Minor
2,697No known interaction
3 Major 129 Moderate 2,697 No interaction
Major

3 interactions

Moderate

129 interactions

Showing 60 of 129 moderate interactions — see all 129 on the Foxglove page.

No interaction 2,697 drugs checked — show the list

We also checked Foxglove 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 Foxglove list.

See the full Foxglove interactions page
See every supplement checked against Clarithromycin, 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
Foxglove monograph › Uses, safety, and every drug interaction in one place Clarithromycin supplement interactions › Every supplement checked against Clarithromycin, ranked by severity Clarithromycin 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 Foxglove and Clarithromycin Together: Common Questions

Can you take Foxglove with Clarithromycin?
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 Foxglove and Clarithromycin 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 Clarithromycin and Foxglove?

Our pharmacists answer your medication & supplement questions — free.

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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.