Evidence-based·Last reviewed May 30, 2026·How we grade evidence

Clostridium butyricum

ProbioticBest in the morningBest taken with food

Useful mainly for people on antibiotics wanting to reduce antibiotic-associated diarrhea.

Quick decision guide

May help most

people on antibiotics wanting to reduce antibiotic-associated diarrhea

Common dosing range

10 million–1 billion CFU/day, divided

When to expect effects

Days to weeks

Watch out for

caution in severe immunocompromise or with central venous catheters

What is it

Clostridium butyricum is a spore-forming, anaerobic gram-positive bacterium that produces butyric acid as a major fermentation product. Several non-toxigenic strains (notably MIYAIRI 588, marketed as MIYA-BM in Japan) are used as probiotics for gastrointestinal health.

Is it worth it for you?

Use this as a quick fit check, not a diagnosis.

Worth considering if…

You are taking antibiotics and want to lower diarrhea risk
You have functional gut symptoms and want a well-tolerated, spore-forming probiotic

Probably skip if…

You are severely immunocompromised or have a central venous line
You expect it to replace IBD medication
You want a guaranteed fix for established C. difficile infection

Evidence at a glance

antibiotic-associated diarrhea prevention

Good Evidence
Effect
Reduced incidence
Best fit
people taking antibiotics, including children
Time
During the antibiotic course

irritable bowel syndrome

Limited Evidence
Effect
Modest symptom improvement
Best fit
adults with IBS, particularly diarrhea-predominant
Time
Weeks

inflammatory bowel disease adjunct

Limited Evidence
Effect
Modest, as add-on
Best fit
people with ulcerative colitis or Crohn's as an adjunct to standard therapy
Time
Weeks

Evidence for 3 uses

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

antibiotic-associated diarrhea prevention

Disease adjunct
Good Evidence

Randomized trials, mostly of the MIYAIRI 588 strain, show C. butyricum reduces the incidence of antibiotic-associated diarrhea. Its spores survive stomach acid and bile and produce butyrate that supports the gut barrier. The evidence is positive though from a limited number of trials.

Effect size
Reduced incidence
Time to effect
During the antibiotic course
Best fit
people taking antibiotics, including children

Bottom line: A reasonable option to lower antibiotic-associated diarrhea risk.

SourceInvestigating et al., 2012 — PubMed

irritable bowel syndrome

Supplement benefit
Limited Evidence

C. butyricum has decades of clinical use in Japan for IBS, and some randomized trials report modest improvements in symptoms and stool pattern. Trial quality and sizes are limited. Effects are modest and variable.

Effect size
Modest symptom improvement
Time to effect
Weeks
Best fit
adults with IBS, particularly diarrhea-predominant

Bottom line: May modestly relieve IBS symptoms, on limited evidence.

SourceSun et al., 2018 — PMCDi et al., 2025 — PMC

inflammatory bowel disease adjunct

Disease adjunct
Limited Evidence

Small studies suggest C. butyricum as an adjuvant may help maintain remission or reduce symptoms in inflammatory bowel disease, plausibly via butyrate's support of colonocytes and the gut barrier. Evidence is preliminary and it is an add-on, not a primary therapy. It should be used alongside standard treatment.

Effect size
Modest, as add-on
Time to effect
Weeks
Best fit
people with ulcerative colitis or Crohn's as an adjunct to standard therapy
Less likely
anyone using it to replace IBD medication

Bottom line: A preliminary adjunct for IBD, not a replacement for standard care.

SourceHuang et al., 2023 — PMCBin et al., 2016 — PMC

How it works

C. butyricum spores survive stomach acid and bile, germinate in the small intestine and colon, and produce short-chain fatty acids, primarily butyrate. Butyrate is the preferred energy source for colonocytes (colon epithelial cells), supports intestinal barrier integrity, modulates immune signaling, and may inhibit growth of pathogenic bacteria such as Clostridium difficile. In clinical use, C. butyricum (MIYAIRI 588) has been used for decades in Japan for diarrhea, irritable bowel syndrome, antibiotic-associated diarrhea, and as adjuvant therapy in inflammatory bowel disease. Several randomized trials support modest benefit for these indications. It is important to distinguish C. butyricum from its toxigenic relative Clostridium botulinum and from Clostridioides difficile. Probiotic strains have a long safety record but should be sourced from reputable manufacturers because rare botulinum-toxin-producing strains have been described in nature.

How to take it

1. Typical dose
10 million–1 billion CFU/day, divided into 2–3 doses
2. Timing
With meals; if on antibiotics, dose a few hours apart
3. With food
With food
4. Split dosing
Divide into 2–3 daily doses
5. How long to try
Through the antibiotic course; 2–4 weeks for functional gut symptoms

What to track

stool frequency/consistency
bloating
abdominal discomfort

2 commercial forms

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

MIYAIRI 588 (MIYA-BM)

The most studied probiotic strain. Widely used in Japan and increasingly elsewhere.

Spore-form; resistant to stomach acid.

C. butyricum spore tablets/powder

Generic preparations; potency varies by manufacturer.

Spores germinate in the small intestine and colon.

Safety

Know the common side effects, key cautions, and who should avoid it.

Common side effects

mild bloating or gas, usually initial

Serious risks

  • rare theoretical bacteremia in vulnerable hosts

Who should avoid it

  • severely immunocompromised people
  • those with central venous catheters or recent abdominal surgery
  • people on immunosuppressants without clinician advice

Pregnancy & breastfeeding

Generally considered safe in pregnancy and breastfeeding at recommended doses, but data are limited.

Interactions

antibioticsMinor

may reduce antibiotic-associated diarrhea; spacing doses a few hours apart is sometimes advised

Choosing a product

What to look for on the label — and what to be skeptical of.

Look for…

named, non-toxigenic strain such as MIYAIRI 588
guaranteed CFU through expiry
reputable manufacturer with quality testing

Be skeptical of…

'cures IBD'
'treats C. difficile infection'
'replaces antibiotics'

Frequently asked questions

Is C. butyricum the same as C. difficile?⌄

No. They are different species. Probiotic strains of C. butyricum produce beneficial butyrate; C. difficile produces toxins that cause severe colitis.

Can probiotic C. butyricum cause botulism?⌄

Approved probiotic strains do not produce botulinum toxin. Rare wild strains have been reported to do so, which is why sourcing matters.

Is it safe with antibiotics?⌄

Yes, and it is often given specifically to prevent antibiotic-associated diarrhea. Spore-formers are relatively antibiotic-resistant.

References by claim

antibiotic-associated diarrhea prevention

Investigating et al., 2012 — PubMed (2012) link

irritable bowel syndrome

Sun et al., 2018 — PMC (2018) link

Di et al., 2025 — PMC (2025) link

inflammatory bowel disease adjunct

Huang et al., 2023 — PMC (2023) link

Bin et al., 2016 — PMC (2016) link

Track Clostridium butyricum with Pilora

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

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Evidence-based·Last reviewed May 30, 2026·Evidence current as of May 30, 2026·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.