Herb & supplement monograph

Lactobacillus Gasseri Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS ·Updated July 2026

What is this page for?

First and foremost: how Lactobacillus Gasseri interacts with medications. The heart of this page is the interaction list — every drug Lactobacillus Gasseri is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Lactobacillus Gasseri is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

Check Lactobacillus Gasseri against your medication

Add one medication

✓ Supplement

Lactobacillus Gasseri

1 Your medication

Start typing any prescription or over-the-counter drug name.

Reviewed by licensed pharmacists Sourced from Natural Medicines

On this page

Lactobacillus Gasseri Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, the overall risk of a clinically significant Lactobacillus Gasseri drug interaction appears low for most people. None of the listed interactions are rated major, and all of them come down to the same single concern rather than many separate risks.

Interactions deserving the most attention

The medications that deserve attention are antibiotics. Because Lactobacillus gasseri is a live probiotic, taking an antibiotic at the same time may kill many of the organisms and reduce the supplement's benefit. Importantly, this concern runs in one direction only: the probiotic may work less well, but the data does not suggest your antibiotic becomes weaker or unsafe.

What the rest of the list means

A long list of interacting medications can look alarming, but here it mostly reflects the many individual antibiotics on the market, all sharing this one predicted effect. The interaction is largely theoretical, based on how antibiotics act against bacteria in general, and it does not point to harm from combining the two. For people not taking an antibiotic, the data raises no notable concerns.

Check your medications against Lactobacillus Gasseri

Based on HelloPharmacist’s Lactobacillus Gasseri interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Lactobacillus Gasseri

182 medications have a known interaction with Lactobacillus Gasseri, graded by severity. Select any drug for the full evidence-based detail.

Don’t want to scroll the list? Just ask.

Tell us the medications you take and we’ll check each one against Lactobacillus Gasseri using our pharmacist-reviewed interaction data.

AI summaries are generated from our Lactobacillus Gasseri interaction data for education only — always confirm with your pharmacist. How we use AI

2,830 drugs

Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
Probable. 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.
Possible. Interaction 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
Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
Each drug listed above links to the full report for that exact Lactobacillus Gasseri combination — clinical detail, likelihood, evidence level, and citations.
Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

The big picture

The kinds of drugs Lactobacillus Gasseri affects

Every type of medication (drug category) Lactobacillus Gasseri is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 1 drug category Lactobacillus Gasseri interacts with

Antibiotic Drugs

Theoretically, taking Lactobacillus gasseri with antibiotic drugs might decrease the effectiveness of L. gasseri.
Lactobacillus gasseri 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. gasseri preparations by at least two hours.

Likelihood Probable Evidence D

Monograph

Lactobacillus Gasseri: Uses, Safety & Side Effects

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Reviewed July 2026 ·

The bottom line

Lactobacillus gasseri is a 'friendly' probiotic bacterium found naturally in the human gut, mouth, and vaginal tract, and in some fermented foods. Early research suggests it may help with digestion, weight management, and vaginal health, but the evidence is limited and far from conclusive. It is generally well tolerated in healthy people, but anyone who is pregnant, breastfeeding, or has a weakened immune system should talk to a pharmacist or doctor first.

Scientific name: Lactobacillus gasseri
Family: Lactobacillaceae
Part used: Live bacterial cells (probiotic strain)
Common forms: Capsules, tablets, powders, fermented dairy products, and combination probiotic supplements

People commonly use it for

Digestive health
Weight and belly fat management
Vaginal and urinary health
Bloating and gut discomfort
General immune support

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance

OverallUse caution

Generally well tolerated in healthy adults, but evidence is limited and some people should avoid it.

PregnancyInsufficient reliable information

There is insufficient reliable information available about the safety of Lactobacillus gasseri during pregnancy and lactation. However, there are curr...

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

There is insufficient reliable information available about the safety of Lactobacillus gasseri during pregnancy and lactation. However, there are curr...

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Lactobacillus gasseri is a type of beneficial bacteria, often called a probiotic. It naturally lives in the human digestive tract, mouth, and the vaginal area, where it is considered part of the normal, healthy mix of microbes.

It is also found in some fermented foods and is sold as a dietary supplement, usually in capsules, tablets, or powders. Many products combine it with other probiotic strains like Bifidobacterium or other Lactobacillus species.

People take L. gasseri hoping to support gut health, manage weight, and promote vaginal and urinary balance. It has become especially popular because of early studies looking at its possible effect on belly fat.

How it works

Like other probiotics, L. gasseri is thought to work by adding helpful bacteria to the gut and other areas of the body. This may help crowd out harmful microbes and support a more balanced microbiome.

It produces lactic acid and other compounds that can lower the local pH and make the environment less friendly to unwanted bacteria. In the vaginal area, this acid-producing role is part of how natural Lactobacillus species help maintain balance.

Researchers have also studied whether it affects how the body absorbs fat and how it interacts with the immune system. Much of this research comes from laboratory and animal studies, so it is not certain how strongly these effects apply to people.

Effectiveness

Does Lactobacillus Gasseri work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by Dr. Brian Staiger, PharmD.

Evidence overview · 17 uses evaluated

17 Insufficient evidence

How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.

2Likely EffectiveGood evidence, though not yet conclusive.

3Possibly EffectiveSome evidence suggests a benefit.

4Possibly IneffectiveSome evidence it may not help.

5Likely IneffectiveFairly strong evidence it doesn’t help.

6IneffectiveStrong evidence it doesn’t work.

7Insufficient Reliable Evidence to RateToo little research to say either way.

For Lactobacillus Gasseri, current evidence isn’t strong enough to rate any specific use. The conditions it has been studied for are listed below.

Also studied for 17 conditions — evidence insufficient to rate

Insufficient Reliable Evidence To Rate Allergic rhinitis (hay fever)