Drug & supplement interaction

Bacillus Coagulans + Oxacillin

Oxacillin brand names: Prostaphlin, Bactocill.

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

Bacillus Coagulans has a moderate interaction with Oxacillin. 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 Oxacillin

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

Moderate

ANTIBIOTIC DRUGS

Why this applies to Oxacillin

Oxacillin 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: this one runs the opposite way from most drug interactions. Oxacillin is a penicillin antibiotic whose whole job is to kill bacteria, and Bacillus coagulans is a probiotic made of live, friendly bacteria. So if the two overlap in your gut, the antibiotic may wipe out a good chunk of those probiotic organisms before they can do anything useful. In short, the antibiotic can weaken the probiotic, not the other way around.

This won't make your oxacillin less effective, and it won't cause new oxacillin side effects. The easy fix is timing: take your probiotic and your antibiotic at least two hours apart. This advice comes mostly from lab-based reasoning, so it's sensible rather than alarming. If you're unsure, your pharmacist can help you space the doses.

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 Oxacillin 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. Oxacillin)
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.

Everything else you take

See Every Supplement That Interacts With Oxacillin

This page covers Bacillus Coagulans only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Oxacillin page lists 56 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Siberian Cocklebur (major), Aristolochia (moderate) and Bacillus Subtilis (moderate).

By severity: 3 major · 42 moderate · 11 minor.

From our pharmacist’s overview on the Oxacillin page

“Kidney harm is the first risk to understand with oxacillin (Bactocill, Prostaphlin), a penicillin antibiotic given for serious staph infections. Siberian cocklebur and asarabacca can each damage the kidneys on their own, and combining them with oxacillin risks compounding that harm; both carry major ratings, as does activated charcoal,…”

Reviewed by 2 · Jul 18, 2026

Open the Oxacillin 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 Oxacillin 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 Oxacillin 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 25%

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

29 days ago today
Medication Oxacillin
Steady interest

#2,507 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 Oxacillin Injection

What Is Oxacillin Injection Used For?

Brand names: Prostaphlin, Bactocill

Oxacillin Injection treats infections caused by penicillinase-producing staphylococci. These are staph bacteria that make an enzyme that destroys regular penicillin. Lab tests should show the bacteria are susceptible to oxacillin.

Doctors may start it before test results are back if a resistant staph infection is suspected. It should not be used for infections caused by bacteria that penicillin G can treat. It should be stopped if tests show the infection is not caused by a resistant staph.

See full Oxacillin Injection 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 Oxacillin, 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 Oxacillin supplement interactions › Every supplement checked against Oxacillin, ranked by severity Oxacillin Injection 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 Oxacillin Together: Common Questions

Can you take Bacillus Coagulans with Oxacillin?
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 Oxacillin 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 Oxacillin 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.