Herb & supplement monograph

Lactobacillus Crispatus 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 Crispatus interacts with medications. The heart of this page is the interaction list — every drug Lactobacillus Crispatus 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 Crispatus 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

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Reviewed by licensed pharmacists Sourced from Natural Medicines

On this page

Lactobacillus Crispatus Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated August 2026

Based on the available evidence, the overall risk of a harmful, clinically significant Lactobacillus Crispatus drug interaction appears low for most people, since the main concern is reduced benefit from the supplement rather than danger from a medication. None of the listed interactions are rated major, and every one of them involves a single theme: antibiotics working against this friendly bacteria.

Interactions deserving the most attention

The only category that stands out is antibiotics. Because Lactobacillus crispatus products contain live organisms, taking an antibiotic at the same time may kill many of those organisms and make the supplement less effective. Notably, this interaction does not make the antibiotic itself less effective or more dangerous, so the concern runs in one direction only.

What the rest of the list means

The long list of interacting medications reflects the fact that many individual antibiotics exist, not many different types of risk. The concern is also largely theoretical, based on how antibiotics work against bacteria in general, rather than on studies showing a meaningful problem in people. In practical terms, this profile points to reduced probiotic benefit, not harm.

Check your medications against Lactobacillus Crispatus

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

Interaction report

Drugs that interact with Lactobacillus Crispatus

182 medications have a known interaction with Lactobacillus Crispatus, 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 Crispatus using our pharmacist-reviewed interaction data.

AI summaries are generated from our Lactobacillus Crispatus 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 Crispatus 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 Crispatus affects

Every type of medication (drug category) Lactobacillus Crispatus 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 Crispatus interacts with

Antibiotic Drugs

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

Likelihood Probable Evidence D

Monograph

Lactobacillus Crispatus: Uses, Safety & Side Effects

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

The bottom line

Lactobacillus crispatus is a 'good' bacterium that naturally dominates a healthy vaginal microbiome and is sold as a probiotic, mainly for vaginal and urinary health. Early research is promising for preventing recurrent bacterial vaginosis and urinary tract infections, but evidence is still limited and product quality varies. Talk with your pharmacist or doctor before using it, especially if you are pregnant or have a weakened immune system.

Scientific name: Lactobacillus crispatus
Family: Lactobacillaceae
Part used: Live bacterial cells (probiotic strain)
Common forms: Oral capsules, vaginal capsules or suppositories, powders, some yogurts and fermented foods

People commonly use it for

Vaginal health support
Preventing recurrent bacterial vaginosis
Reducing recurrent urinary tract infections
Yeast infection support
General microbiome balance

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

Safety at a glance

OverallUse caution

Generally considered safe for healthy people, but quality and evidence vary by product.

PregnancyInsufficient reliable information

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

Read the full pregnancy detail

BreastfeedingInsufficient reliable information

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

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.

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Overview

Lactobacillus crispatus is a type of friendly bacteria that lives naturally in the human body, especially in the vagina and the gut. In many healthy women, this species is the most common bacterium in the vagina, where it helps keep the environment slightly acidic.

Because of this natural role, L. crispatus is sold as a probiotic supplement. It comes as oral capsules and powders as well as vaginal capsules or suppositories. It is also found in some fermented foods, though usually in much smaller amounts than in dedicated supplements.

People most often take it to support vaginal and urinary tract health, or to help restore a balanced microbiome after infections or antibiotic use.

How it works

A healthy vagina is normally acidic, and Lactobacillus crispatus helps maintain that acidity by producing lactic acid. This low pH makes it harder for harmful bacteria and some yeasts to grow.

Laboratory studies suggest the bacteria may also produce hydrogen peroxide and other substances that discourage unwanted microbes, and that they can stick to the cells lining the vagina, helping to crowd out less friendly organisms.

Many of these mechanisms come from laboratory and small human studies. They help explain why the strain may be helpful, but they do not by themselves prove how well any specific product works in real life.

Effectiveness

Does Lactobacillus Crispatus work?

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

Evidence overview · 10 uses evaluated

1 Possibly effective 9 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.

Possibly Effective Bacterial vaginosis