Drug & supplement interaction

Black Haw + Fidaxomicin

Fidaxomicin brand name: Dificid.

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 Black Haw and Fidaxomicin 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.

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Interaction report

Black Haw and Fidaxomicin

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 Fidaxomicin and Black Haw 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Black Haw at all — not against Fidaxomicin, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Black Haw safety at a glance

Black Haw overall Use caution Generally used in traditional medicine, but human safety data are limited.
Pregnancy Possibly Unsafe When used orally. Some evidence suggests black haw has uterine relaxant effects; avoid using. Read the full pregnancy detail
Breastfeeding Avoid Not enough safety information exists for nursing mothers.

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Fidaxomicin and Black Haw? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Fidaxomicin’s Own FDA Label Lists

This is not an interaction — none of it involves Black Haw. These are the most notable effects listed in the ADVERSE REACTIONS section of Fidaxomicin’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both. 3 of them are worth acting on rather than waiting out — marked below.

  • Anemia Worth acting on
  • A low white blood cell count Worth acting on
  • Bleeding or bruising Worth acting on
  • Diarrhea mentioned in 14.7% of FDA reports for Fidaxomicin
  • Stomach pain mentioned in 3.6% of FDA reports for Fidaxomicin
  • Fever
  • Constipation
  • Nausea mentioned in 5.2% of FDA reports for Fidaxomicin
  • A skin rash
  • Vomiting

From the ADVERSE REACTIONS section of the FDA label for Fidaxomicin. Read the label on DailyMed › Where a percentage is shown, it is the share of 2,385 voluntary FDA FAERS reports for Fidaxomicin that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Black Haw’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Black Haw side to compare — that is a limit of the record, not a statement that Black Haw has no side effects.

Special populations

Black Haw in Pregnancy & Breastfeeding

Pregnancy Possibly Unsafe

When used orally. Some evidence suggests black haw has uterine relaxant effects; avoid using.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

Overlapping uses

What Fidaxomicin Is Prescribed For, and What Black Haw Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Fidaxomicin is a prescription medicine with approved uses on its FDA label. Black Haw is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Fidaxomicin is prescribed for: Fidaxomicin treats C. difficile-associated diarrhea (CDAD) — a bacterial infection in the gut caused by Clostridioides difficile that leads to significant diarrhea and intestinal inflammation. Fidaxomicin tablets are approved for adult patients. Dificid (as tablets or oral suspension) is approved for both adults and children 6 months of age and older.

Read the rest of what Fidaxomicin is prescribed for

Because fidaxomicin works almost entirely inside the gut and is barely absorbed into the bloodstream, it is only effective against C. difficile and should not be used for any other type of infection.

Black Haw has been studied for:

  • Diarrhea studied, not established Black Haw has been studied for this. Natural Medicines rates the evidence: Insufficient Reliable Evidence To Rate Read what the research shows

    Black Haw for diarrhea

    Although there has been interest in using oral black haw for diarrhea, there is insufficient reliable information about the clinical effects of black haw for this purpose.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Fidaxomicin on your own; if you are taking Black Haw for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Black Haw or Fidaxomicin

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 Haw or Fidaxomicin, 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 Fidaxomicin

This page covers Black Haw only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Fidaxomicin page lists 92 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Oleander (major), St. John's Wort (major), Bacillus Coagulans (moderate) and Bacillus Subtilis (moderate).

By severity: 3 major · 71 moderate · 18 minor.

From our pharmacist’s overview on the Fidaxomicin page

“If you are taking fidaxomicin (Dificid) for a Clostridioides difficile infection, supplements are not a side issue, because anything that weakens this drug risks letting a hard-to-treat infection come back. Three entries rated major top my concerns.”

Reviewed by 2 · Jul 18, 2026

Open the Fidaxomicin interaction page

One more smart check

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

We hold 20 real supplement products containing Black Haw, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Black Haw. Even though Black Haw itself has no known interaction with Fidaxomicin, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Black Haw and Fidaxomicin 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 Haw
Steady interest

#1,138 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Fidaxomicin
Top half

#1,039 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 Black Haw reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Black Haw and Fidaxomicin records this page draws on were last updated July 11, 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 Black Haw

What is Black Haw?

Black Haw
  • Menstrual cramps
  • Uterine spasms
  • Threatened miscarriage (traditional)
  • Menopause-related discomfort
  • General muscle cramps

Black Haw is a traditional herbal bark long used to ease menstrual cramps and uterine spasms, but modern human studies are very limited. It contains compounds that may relax smooth muscle, but its effectiveness is not well proven, and it should be used with caution, especially during pregnancy. Talk to a pharmacist or doctor before trying it.

Viburnum prunifolium · Adoxaceae · Bark of the stem and root · Tea (decoction), tincture, liquid extract, capsules, dried bark

An interaction check asks whether these two react with each other — it does not ask whether Black Haw is a good idea for someone in your situation. Here is what our Black Haw record says about it on its own.

Black Haw: dosing

There is no established standardized dose for Black Haw. Traditional preparations include teas (decoctions of the bark), tinctures, and liquid extracts, but reliable dosing has not been confirmed by modern research.If you choose to use a product, follow the directions on the label and do not exceed the recommended amount.

From our Black Haw monograph — the full record covers uses, side effects and every documented interaction.

Read the full Black Haw monograph & all interactions
Medication

About Fidaxomicin

What Is Fidaxomicin Used For?

Brand name: Dificid

Fidaxomicin treats C. difficile-associated diarrhea (CDAD) — a bacterial infection in the gut caused by Clostridioides difficile that leads to significant diarrhea and intestinal inflammation. Fidaxomicin tablets are approved for adult patients. Dificid (as tablets or oral suspension) is approved for both adults and children 6 months of age and older.

Because fidaxomicin works almost entirely inside the gut and is barely absorbed into the bloodstream, it is only effective against C. difficile and should not be used for any other type of infection.

Most-Reported Side Effects for Fidaxomicin

From FAERS, the FDA’s public side-effect reporting system (2,385 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Clostridium difficile infection 480 reports
Diarrhea 350 reports
Disease recurrence 179 reports
Clostridium difficile colitis 161 reports
Nausea 125 reports
See full Fidaxomicin drug information
Keep checking

Other Drugs & Black Haw

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Black Haw list.

See the full Black Haw interactions page
See every supplement checked against Fidaxomicin, ranked by severity
Evidence & sources

Black Haw References

The 1 references that drive our Black Haw 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. Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.

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 Black Haw and Fidaxomicin Together: Common Questions

Is it safe to take Black Haw with Fidaxomicin?
We do not list a known interaction between Black Haw and Fidaxomicin. 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.
Are Black Haw and Fidaxomicin used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Black Haw in each. That is a conversation for your prescriber, especially if Fidaxomicin is being adjusted to a target.
Does Fidaxomicin interact with any supplements?
Yes. Fidaxomicin has documented interactions with 92 supplements in our database — Black Haw is not one of them. The Fidaxomicin 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

Black Haw monograph Uses, safety profile, and every drug interaction in one place Fidaxomicin drug information The full plain-English guide to this medication Fidaxomicin supplement interactions Every supplement checked against Fidaxomicin, 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 1 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Fidaxomicin and Black Haw?

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.