Lactococcus casei

ProbioticLactococcus

What is it

The label name 'Lactococcus casei' is most likely a misnomer for Lacticaseibacillus casei (formerly Lactobacillus casei), a widely used probiotic species. True Lactococcus is a related but distinct genus used mainly in dairy fermentation.

Evidence for 2 uses

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Antibiotic-associated diarrhea

Good Evidence

Several trials and meta-analyses show L. casei strains reduce incidence of antibiotic-associated diarrhea.

Irritable bowel symptoms

Limited Evidence

Some trials show modest improvements in IBS symptoms; strain and dose matter.

How it works

Lacticaseibacillus casei strains colonize the small intestine, produce lactic acid, support the mucosal barrier, and modulate gut immunity. Specific strains have been studied for diarrhea, irritable bowel symptoms, and immune support. The DN-114 001 strain (Actimel) is the most-researched commercial strain. Lactococcus (the dairy genus) primarily plays a role in cheese making rather than human probiotic supplementation.

Dosage

Typical probiotic doses are 1-10 billion CFU/day. Studied strains often use 10-100 billion CFU in clinical trials.

When and how to take it

Can be taken with or without food. With food may improve survival through the stomach.

2 commercial forms

Compare the main delivery options and what they’re best suited for.

Lacticaseibacillus casei (probiotic)

Standard probiotic species.

Strain identity matters for studied effects.

L. casei DN-114 001 (Actimel)

Found in fermented dairy drinks.

Studied commercial dairy strain.

Safety

Generally well-tolerated in healthy people. Mild bloating or gas during the first few days. Rare bacteremia in severely immunocompromised individuals.

Who should be cautious

Avoid in severe immunosuppression, central venous catheters, or critical illness. People with prosthetic heart valves should consult a clinician. Pregnancy data are limited but no signal of harm at typical doses.

Interactions

Few clinically significant interactions. Antibiotic timing matters; separate by 2-3 hours if using non-resistant strains.

Food sources

Yogurt, fermented dairy

Amount
1 serving
%DV
—

Frequently asked questions

Is Lactococcus the same as Lactobacillus?⌄

No. They are different genera. Most probiotic 'casei' products use Lacticaseibacillus (formerly Lactobacillus) casei, not true Lactococcus.

Do I need a specific strain?⌄

Effects are often strain-specific. Look for the strain designation (e.g., DN-114 001) on the label if you want a researched effect.

References

Lactococcus casei on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Lactococcus casei (PubMed search) — PubMed link

Track Lactococcus casei with Pilora

Set up dose reminders, check interactions, and join the community in the Pilora iPhone app.

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.