Drug & supplement interaction

Bacillus Coagulans + Rifaximin

Rifaximin brand name: Xifaxan.

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

Bacillus Coagulans has a moderate interaction with Rifaximin. Theoretically, taking antibiotics with Bacillus coagulans might decrease the effectiveness of B.

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

Bacillus Coagulans and Rifaximin

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

Moderate

ANTIBIOTIC DRUGS

Why this applies to Rifaximin

Rifaximin falls under ANTIBIOTIC DRUGS — the group Bacillus Coagulans interacts with.

Theoretically, taking antibiotics with Bacillus coagulans might decrease the effectiveness of B. coagulans.
B. coagulans preparations usually contain live and active organisms. Therefore, simultaneously taking antibiotics might kill a significant number of the organisms. Tell patients to separate administration of antibiotics and B. coagulans preparations by at least two hours.
Severity Moderate Likelihood Probable Evidence D

Interaction 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..

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

Here's the simple version: Rifaximin is an antibiotic, and Bacillus coagulans is a live probiotic. When you take them at the same time, the antibiotic can kill off some of those beneficial bacteria before they get a chance to do their job. So the concern here isn't that your rifaximin becomes dangerous or stops working. It's the other way around: the probiotic may simply be less effective.

Good news is this is easy to manage. A common suggestion is to space them out by at least two hours so the antibiotic isn't directly wiping out the probiotic dose. Keep in mind this is mostly a theoretical, lab-based concern, so don't panic. Just check with your pharmacist or doctor about timing, especially since rifaximin is often used for gut conditions where probiotics are popular.

Contact Dr. Brian directly if you have additional questions on this interaction

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

Bacillus Coagulans Also Interacts With Other Medications

Bacillus Coagulans has 181 moderate known drug interactions in our database — the Rifaximin one above is one of them. If you take anything else, check it against the full list below.

Moderate 181 No known interaction 2,649 (incl. Rifaximin)
Taking anything else?

Check Another of Your Medications Against Bacillus Coagulans

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

From our Q&A

Questions About Bacillus Coagulans or Rifaximin

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

This page covers Bacillus Coagulans only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Rifaximin page lists 44 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Bacillus Subtilis (moderate), Bifidobacterium Animalis Subsp. Lactis (moderate), Bifidobacterium Bifidum (moderate) and Bifidobacterium Breve (moderate).

By severity: 1 major · 33 moderate · 10 minor.

From our pharmacist’s overview on the Rifaximin page

“Activated charcoal is the one entry here I would treat as a hard stop while taking rifaximin (Xifaxan). Charcoal binds drugs in the gut and can cut how much gets absorbed, and it carries the only major rating among the 44 supplements on this page.”

Reviewed by 2 · Jul 18, 2026

Open the Rifaximin interaction page

One more smart check

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

We hold 1,895 real supplement products containing Bacillus Coagulans, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Bacillus Coagulans. Your product may carry other ingredients that interact with Rifaximin too, on top of Bacillus Coagulans — 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 Bacillus Coagulans and Rifaximin 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 Bacillus Coagulans
Top 10%

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

29 days ago today
Medication Rifaximin
Top half

#1,074 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 Bacillus Coagulans

What is Bacillus Coagulans?

Bacillus Coagulans
  • Constipation
  • Irritable bowel syndrome (IBS)
  • Diarrhea
  • General digestive health
  • Immune support
  • Bloating and gas

Bacillus coagulans is a spore-forming probiotic that survives stomach acid well and may help with some digestive problems such as IBS, constipation, and certain types of diarrhea. The evidence is promising but still limited, and quality and strains vary between products. It is generally well tolerated in healthy people, but people with weak immune systems and those who are pregnant or breastfeeding should talk to a doctor first.

Read the full Bacillus Coagulans monograph & all interactions
Medication

About Rifaximin

What Is Rifaximin Used For?

Brand name: Xifaxan

Xifaxan (rifaximin) tablets treat three distinct conditions. For travelers' diarrhea caused by Escherichia coli, it is approved for adults and children 12 and older. For irritable bowel syndrome with diarrhea (IBS-D), it is approved for adults. It is also used in adults to reduce the chance that hepatic encephalopathy (confusion and other brain symptoms caused by liver disease) will come back.

Important limits apply: Xifaxan should not be used for travelers' diarrhea that comes with fever, blood in the stool, or when a pathogen other than E. coli is suspected. It is also not suitable for bacterial infections outside the gut, because very little of the drug is absorbed into the bloodstream.

See full Rifaximin drug information
Keep checking

Other Drugs & Bacillus Coagulans

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

0Major
181Moderate
0Minor
2,648No known interaction
181 Moderate 2,648 No interaction
Moderate

181 interactions

Showing 60 of 181 moderate interactions — see all 181 on the Bacillus Coagulans page.

No interaction 2,648 drugs checked — show the list

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

Showing the 60 most looked-up of 2,648 medications checked with no known interaction — see the full Bacillus Coagulans list.

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

Can you take Bacillus Coagulans with Rifaximin?
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 Bacillus Coagulans and Rifaximin 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 Rifaximin and Bacillus Coagulans?

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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.