Drug & supplement interaction

Probiotics + Griseofulvin

Griseofulvin brand names: Fulvicin PG, Fulvicin-U/F, Grisactin Ultra, Grisactin.

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

Probiotics has a minor interaction with Griseofulvin. Theoretically, taking antifungals with certain probiotics might decrease the effectiveness of probiotics.

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

Probiotics and Griseofulvin

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

Minor

ANTIFUNGALS

Why this applies to Griseofulvin

Griseofulvin falls under ANTIFUNGALS — the group Probiotics interacts with.

Theoretically, taking antifungals with certain probiotics might decrease the effectiveness of probiotics.
Some probiotics such as Saccharomyces boulardii are fungi. Therefore, simultaneously taking antifungals might kill a significant number of these organisms.
Severity Minor 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 thing to know about this pairing: it actually runs in the opposite direction from most interactions. Griseofulvin is an antifungal, and one popular probiotic, Saccharomyces boulardii, is itself a friendly yeast (a fungus). So the worry isn't that the probiotic changes your griseofulvin levels or makes its side effects (like headache, upset stomach, or sun sensitivity) worse. It's that the antifungal could kill off some of that yeast-based probiotic, making the probiotic less helpful.

Keep in mind this is only a theoretical concern based on how these products work, not proven harm. If you're taking a yeast-based probiotic for a real reason, ask your pharmacist whether to space the doses apart or pick a bacteria-based product instead.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
  2. Lewis SJ, Freedman AR. Review article: the use of biotherapeutic agents in the prevention and treatment of gastrointestinal disease. Aliment Pharmacol Ther 1998;12:807-22. PubMed

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

Probiotics Also Interacts With Other Medications

Probiotics has 182 moderate, 39 minor known drug interactions in our database — the Griseofulvin one above is one of them. If you take anything else, check it against the full list below.

Moderate 182 Minor 39 No known interaction 2,609 (incl. Griseofulvin)
Taking anything else?

Check Another of Your Medications Against Probiotics

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

From our Q&A

Questions About Probiotics or Griseofulvin

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

This page covers Probiotics only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Griseofulvin page lists 61 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Alfalfa (moderate), Alkanna (moderate), Alpine Ragwort (moderate) and Angelica Archangelica (moderate).

By severity: 1 major · 47 moderate · 13 minor.

From our pharmacist’s overview on the Griseofulvin page

“If you take griseofulvin for a fungal infection of the skin, scalp, or nails, give this list of 61 ingredients real attention. The single major entry is activated charcoal, which binds the drug in your gut so less of it reaches your blood and the infection gets less treatment.”

Reviewed by 2 · Jul 18, 2026

Open the Griseofulvin interaction page

One more smart check

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

We hold 15 real supplement products containing Probiotics, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Probiotics. Your product may carry other ingredients that interact with Griseofulvin too, on top of Probiotics — 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 Probiotics and Griseofulvin 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 Probiotics
Top half

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

29 days ago today
Medication Griseofulvin
Top half

#1,035 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 Probiotics

What is Probiotics?

  • Digestive health and regularity
  • Antibiotic-associated diarrhea
  • Irritable bowel syndrome (IBS)
  • Vaginal and urinary health
  • Immune support
  • General gut microbiome balance

Probiotics are live 'friendly' microbes that may help certain digestive conditions, such as antibiotic-associated diarrhea and some cases of IBS, though benefits depend heavily on the specific strain and dose. They are generally well tolerated for healthy people but should be used with caution by those with serious illness or weakened immune systems. Talk with your pharmacist or doctor to pick a product that matches your goal.

Read the full Probiotics monograph & all interactions
Medication

About Griseofulvin

What Is Griseofulvin Used For?

Brand names: Fulvicin PG, Fulvicin-U/F, Grisactin Ultra, Grisactin

Griseofulvin treats fungal skin, hair and nail infections caused by dermatophytes (fungi that live on skin, hair and nails). These are often called ringworm. It is used when the infection is not adequately treated by creams or other topical products.

It does not work for bacterial infections, yeast infections (candidiasis) or tinea versicolor. The label says it is not justified for minor infections that a topical product alone will clear. Oral suspension and tablet products (Griseofulvin, Griseofulvin Microsize and Ultramicrosize Griseofulvin) share this same list of uses.

See full Griseofulvin drug information
Keep checking

Other Drugs & Probiotics

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

0Major
182Moderate
39Minor
2,608No known interaction
182 Moderate 39 Minor 2,608 No interaction
Moderate

182 interactions

Showing 60 of 182 moderate interactions — see all 182 on the Probiotics page.

Minor

39 interactions

No interaction 2,608 drugs checked — show the list

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

Showing the 60 most looked-up of 2,608 medications checked with no known interaction — see the full Probiotics list.

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

Can you take Probiotics with Griseofulvin?
There is only a minor interaction, which is usually not serious. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Probiotics and Griseofulvin interaction?
We rate it Minor. This interaction is generally not clinically significant, but it remains worth noting and discussing with your pharmacist.

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

Still Have a Question About Griseofulvin and Probiotics?

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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.