Drug & supplement interaction

Ligilactobacillus Salivarius + Nafcillin

Nafcillin brand name: Nallpen.

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

Ligilactobacillus Salivarius has a moderate interaction with Nafcillin. Theoretically, taking Ligilactobacillus salivarius with antibiotic drugs might decrease the effectiveness of L.

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

Ligilactobacillus Salivarius and Nafcillin

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

Moderate

ANTIBIOTIC DRUGS

Why this applies to Nafcillin

Nafcillin falls under ANTIBIOTIC DRUGS — the group Ligilactobacillus Salivarius interacts with.

Theoretically, taking Ligilactobacillus salivarius with antibiotic drugs might decrease the effectiveness of L. salivarius.
Ligilactobacillus salivarius 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 L. salivarius 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 thing to keep in mind: this interaction runs in one direction, and it's the probiotic that takes the hit, not your antibiotic. Nafcillin is a penicillin that works by killing bacteria. Since Ligilactobacillus salivarius is a live, friendly bacterium, an antibiotic like nafcillin can wipe out a good chunk of those organisms before they ever get to work. So you may simply get less benefit from the probiotic.

The good news is your nafcillin treatment stays just as effective, and there's no added safety risk to you. This is a theory based on how these products behave, not strong human studies. If you want to keep taking the probiotic, a simple fix is spacing them apart. Your pharmacist can help you time the doses (often at least two hours apart) so both have a fair shot.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Pierce A. The American Pharmaceutical Association Practical Guide to Natural Medicines. New York: The Stonesong Press, 1999:19.

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

Ligilactobacillus Salivarius Also Interacts With Other Medications

Ligilactobacillus Salivarius has 181 moderate known drug interactions in our database — the Nafcillin 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. Nafcillin)
Taking anything else?

Check Another of Your Medications Against Ligilactobacillus Salivarius

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

Everything else you take

See Every Supplement That Interacts With Nafcillin

This page covers Ligilactobacillus Salivarius only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Nafcillin page lists 58 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Asarabacca (major), Siberian Cocklebur (major), Alkanna (moderate), Alpine Ragwort (moderate) and Aristolochia (moderate).

By severity: 2 major · 54 moderate · 2 minor.

From our pharmacist’s overview on the Nafcillin page

“Anyone on nafcillin (Nallpen) is usually fighting a serious staph infection, and that makes this a time to be genuinely careful with supplements. Of the 58 with a known interaction on file, the two rated major, Siberian cocklebur and asarabacca, both stress the kidneys and could compound damage while you are being treated.”

Reviewed by 2 · Jul 18, 2026

Open the Nafcillin interaction page

How much people look this up

Where Ligilactobacillus Salivarius and Nafcillin 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 Ligilactobacillus Salivarius
Steady interest

#1,246 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Nafcillin
Steady interest

#2,634 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 Ligilactobacillus Salivarius

What is Ligilactobacillus Salivarius?

  • Digestive and gut health
  • Oral and dental health
  • Immune support
  • Vaginal and urinary health
  • General probiotic supplementation

Ligilactobacillus salivarius (formerly called Lactobacillus salivarius) is a probiotic bacterium found naturally in the mouth and gut of humans and animals. People take it to support digestion, oral health, and immunity, but solid human evidence is still limited for most uses. It is generally well tolerated in healthy people, but those with weakened immune systems should check with a doctor first.

Read the full Ligilactobacillus Salivarius monograph & all interactions
Medication

About Nafcillin Injection

What Is Nafcillin Injection Used For?

Brand name: Nallpen

NAFCILLIN Injection is used to treat infections caused by staphylococci — specifically strains that produce an enzyme called penicillinase, which makes them resistant to regular penicillin. Susceptibility testing is performed to confirm the bacteria will respond to nafcillin before or shortly after starting treatment.

Nafcillin may also be started right away when a resistant staph infection is strongly suspected, even before test results are available. It should not be used for infections caused by bacteria that would respond to standard penicillin G, or for infections caused by non-staph organisms.

See full Nafcillin Injection drug information
Keep checking

Other Drugs & Ligilactobacillus Salivarius

Browse every other medication we’ve checked against Ligilactobacillus Salivarius — 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 Ligilactobacillus Salivarius page.

No interaction 2,648 drugs checked — show the list

We also checked Ligilactobacillus Salivarius 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 Ligilactobacillus Salivarius list.

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

Can you take Ligilactobacillus Salivarius with Nafcillin?
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 Ligilactobacillus Salivarius and Nafcillin 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 Nafcillin and Ligilactobacillus Salivarius?

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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.