Drug & supplement interaction

Lactobacillus Delbrueckii + Tetracycline

Tetracycline brand names: Sumycin, Sumycin 250, Tetrex BID, Achromycin V, Robitet, and others.

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

Lactobacillus Delbrueckii has a moderate interaction with Tetracycline. 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 Tetracycline

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

Moderate

ANTIBIOTIC DRUGS

Why this applies to Tetracycline

Tetracycline 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 thing to keep in mind with this pairing: tetracycline is an antibiotic, and its whole job is to kill bacteria. A probiotic like Lactobacillus delbrueckii is made of live, helpful bacteria. So if you swallow them at the same time, the tetracycline can wipe out a good chunk of those probiotic organisms before they ever get to work. In short, your antibiotic doesn't get weaker, but the probiotic may not do much for you.

The easy fix is timing. Separating the two by at least two hours helps the probiotic survive. This is based on how the drugs work rather than hard studies, so it's a sensible precaution, not a danger. Run your full schedule by your pharmacist, since tetracycline also needs to be spaced away from dairy, calcium, and antacids.

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 Tetracycline 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. Tetracycline)
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.

From our Q&A

Questions About Lactobacillus Delbrueckii or Tetracycline

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

This page covers Lactobacillus Delbrueckii only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Tetracycline page lists 164 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Beer (major), Oleander (major) and Siberian Cocklebur (major).

By severity: 7 major · 136 moderate · 21 minor.

Open the Tetracycline 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 Tetracycline 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 Tetracycline 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%

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

29 days ago today
Medication Tetracycline
Top 25%

#380 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
Medication

About Tetracycline

What Is Tetracycline Used For?

Brand names: Sumycin, Sumycin 250, Tetrex BID, Achromycin V, Robitet, Sumycin 500, Tetra, Nor-Tet, Tetracyn, Tetrex, Achromycin, Terramycin IM

Oral tetracycline (tablets and capsules) treats infections caused by susceptible bacteria, including upper and lower respiratory tract infections, skin and soft tissue infections, and sexually transmitted infections such as those caused by Chlamydia trachomatis. It is also used for tick- and flea-borne illnesses like Rocky Mountain spotted fever and typhus, as well as cholera, brucellosis, tularemia, plague, and several other serious bacterial infections.

Topical tetracycline products — including ointments, sprays, and solutions sold under brand names such as Tetracyte, Vitastem, Viabecline, Honestly Battleborn, and ViaDerma Care — are over-the-counter first-aid products used to help prevent skin infection in minor cuts, scrapes, and burns. These topical products are not used for systemic (whole-body) infections.

See full Tetracycline drug information
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 Tetracycline, 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 Tetracycline supplement interactions › Every supplement checked against Tetracycline, ranked by severity Tetracycline 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 Lactobacillus Delbrueckii and Tetracycline Together: Common Questions

Can you take Lactobacillus Delbrueckii with Tetracycline?
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 Tetracycline 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 Tetracycline 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.