Drug & supplement interaction

Lactobacillus Delbrueckii + Nalidixic Acid

Nalidixic Acid brand name: NegGram.

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

Lactobacillus Delbrueckii has a moderate interaction with Nalidixic Acid. Theoretically, taking Lactobacillus delbrueckii 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

Lactobacillus Delbrueckii and Nalidixic Acid

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

Moderate

ANTIBIOTIC DRUGS

Why this applies to Nalidixic Acid

Nalidixic Acid falls under ANTIBIOTIC DRUGS — the group Lactobacillus Delbrueckii interacts with.

Theoretically, taking Lactobacillus delbrueckii with antibiotic drugs might decrease the effectiveness of L. delbrueckii.
Lactobacillus delbrueckii 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. delbrueckii 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 key thing to know: this interaction goes in one direction only. Nalidixic Acid (NegGram) is an antibiotic, and its whole job is to kill bacteria. Since Lactobacillus delbrueckii is a live probiotic made of friendly bacteria, taking them at the same time means the antibiotic may wipe out a good chunk of those probiotic organisms before they ever get to work. So the loser here is the probiotic, not your antibiotic. Your Nalidixic Acid will still treat your infection just fine.

This is a theoretical concern based on how these products work, not a dangerous one. A simple fix: take your probiotic at least two hours apart from your antibiotic dose. As always, run any new supplement by your pharmacist or doctor first.

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

Lactobacillus Delbrueckii Also Interacts With Other Medications

Lactobacillus Delbrueckii has 181 moderate known drug interactions in our database — the Nalidixic Acid 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. Nalidixic Acid)
Taking anything else?

Check Another of Your Medications Against Lactobacillus Delbrueckii

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

Everything else you take

See Every Supplement That Interacts With Nalidixic Acid

This page covers Lactobacillus Delbrueckii only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Nalidixic Acid page lists 146 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Apple (major), Asarabacca (major), Beer (major) and Grapefruit (major).

By severity: 8 major · 118 moderate · 20 minor.

Open the Nalidixic Acid interaction page

One more smart check

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

We hold 1,200 real supplement products containing Lactobacillus Delbrueckii, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Lactobacillus Delbrueckii. Your product may carry other ingredients that interact with Nalidixic Acid too, on top of Lactobacillus Delbrueckii — 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 Lactobacillus Delbrueckii and Nalidixic Acid 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 Lactobacillus Delbrueckii
Top 25%

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

29 days ago today
Medication Nalidixic Acid
Steady interest

#1,793 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 Lactobacillus Delbrueckii

What is Lactobacillus Delbrueckii?

  • Digestive health
  • Lactose digestion support
  • Diarrhea
  • Gut microbiome balance
  • Immune support

Lactobacillus delbrueckii is a 'friendly' bacterium used in food fermentation and sold as a probiotic, often as part of multi-strain products. It is generally considered safe for healthy people, but solid human evidence for most specific health claims is limited. Talk to a pharmacist or doctor before using it, especially if you have a weakened immune system or serious illness.

Read the full Lactobacillus Delbrueckii monograph & all interactions
Keep checking

Other Drugs & Lactobacillus Delbrueckii

Browse every other medication we’ve checked against Lactobacillus Delbrueckii — 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 Lactobacillus Delbrueckii page.

No interaction 2,648 drugs checked — show the list

We also checked Lactobacillus Delbrueckii 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 Lactobacillus Delbrueckii list.

See the full Lactobacillus Delbrueckii interactions page
See every supplement checked against Nalidixic Acid, 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
Lactobacillus Delbrueckii monograph › Uses, safety, and every drug interaction in one place Nalidixic Acid supplement interactions › Every supplement checked against Nalidixic Acid, 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 Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Lactobacillus Delbrueckii and Nalidixic Acid Together: Common Questions

Can you take Lactobacillus Delbrueckii with Nalidixic Acid?
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 Lactobacillus Delbrueckii and Nalidixic Acid 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 Nalidixic Acid and Lactobacillus Delbrueckii?

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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.