Home Ingredients Bacillus clausii (Enterogermina® / Erceflora)
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Bacillus clausii (Enterogermina® / Erceflora)

Bacillus clausii — strains O/C, N/R, SIN, T
Evidence Level
Strong
3 Clinical Trials
8 Documented Benefits
4/5 Evidence Score

Bacillus clausii is a spore-forming probiotic commercialized as Enterogermina® (Sanofi/Italy) and Erceflora® in some markets. The spore form is heat-stable and survives stomach acid intact — a distinguishing advantage over lactic acid bacteria probiotics. Clinical evidence supports use in acute diarrhea (children and adults), antibiotic-associated diarrhea prevention, and recurrent respiratory infections in children. The product has been marketed in Europe and emerging markets for decades, with broad regulatory acceptance. The honest framing: a robust spore-forming probiotic with reasonable evidence for specific acute and antibiotic-related GI conditions; less established for chronic gut conditions like IBS. Particularly useful in settings where refrigeration of probiotics is impractical due to its heat-stable spore form.

Studied Dose 2 billion spores (2×10⁹ CFU) 2-3 times daily; AAD prevention: 2 billion spores twice daily during antibiotic therapy plus 1 week after.
Active Compound Bacillus clausii spores — strains O/C, N/R, SIN, T (Enterogermina® preparation). Polyantibiotic-resistant spore-forming bacterium.

Benefits

Acute diarrhea treatment

B. clausii reduces duration and severity of acute diarrhea in children and adults across multiple randomized trials. Effect sizes are moderate; benefits seen within days of starting supplementation. One of the better-evidenced uses for this strain.

Supported by Trial 1, Trial 3

Antibiotic-associated diarrhea prevention

Taken alongside antibiotic therapy, B. clausii reduces the incidence of antibiotic-associated diarrhea. Heat-stable spore form means it survives stomach acid intact and isn't killed by concurrent antibiotic doses — unlike lactic acid bacteria probiotics.

Supported by Trial 2

H. pylori eradication adjunct

Used alongside standard triple therapy for H. pylori infection, B. clausii reduces side effects of antibiotic therapy and may improve patient compliance. Adjunct support; not standalone treatment.

Supported by Trial 2

Recurrent respiratory infections in children

Trials in children with recurrent respiratory infections show reduced infection frequency with B. clausii supplementation over months. Reflects gut-immune axis effects extending beyond GI applications.

Supported by Trial 1, Trial 3

Spore-form survival advantage

The spore form is heat-stable and acid-resistant, surviving stomach acid intact to germinate in the small intestine. Distinguishing mechanism — most probiotic forms require refrigeration and significant doses to compensate for stomach acid loss.

Supported by Trial 1

Allergic rhinitis support

Some clinical evidence in pediatric allergic rhinitis suggests B. clausii may reduce symptoms over weeks of use. Effects are modest and not the strongest application, but consistent with broader gut-immune modulation.

Supported by Trial 1, Trial 3

Antimicrobial peptide production

B. clausii produces antimicrobial peptides (bacteriocins) active against pathogenic bacteria. Mechanism contributes to its acute diarrhea benefits and provides plausible biological rationale for its decades of clinical use.

Supported by Trial 1, Trial 3

Decades-long safety record

Marketed in Europe and emerging markets since the 1950s with extensive real-world safety data across millions of users. GRAS status and well-tolerated even in young children and immunocompromised patients.

Supported by Trial 3

Mechanism of action

1

Intrinsic polyantibiotic resistance (uniquely positioned)

Natural genetic resistance to multiple antibiotic classes — distinct from acquired resistance via plasmid transfer. Allows the probiotic to survive and exert effects during concurrent antibiotic therapy, the central practical advantage for AAD prevention.

2

Spore-forming durability

Bacterial endospores are dormant, resistant structures surviving heat, acid, bile, and processing. Spores germinate to active vegetative cells in the small intestine where they exert effects.

3

Antimicrobial peptide production

B. clausii produces antimicrobial peptides active against C. difficile and other opportunistic pathogens. Direct competitive antimicrobial mechanism beyond niche occupation.

4

Microbiota restoration during dysbiosis

During antibiotic-induced dysbiosis, B. clausii occupies niche space and supports recovery of native commensals. Mechanism for reduced AAD development.

5

Anti-inflammatory effects

Reduces pro-inflammatory cytokine production in the gut mucosa — supporting recovery from inflammatory diarrhea episodes.

Clinical trials

1
PMC12182463 — Pediatric Acute Gastroenteritis Evidence Synthesis (pivotal)

Evidence review and pooled analysis of 11 clinical trials plus 3 non-randomized controlled trials in pediatric acute gastroenteritis.

11 clinical trials pooled

Evidence review and pooled analysis of 11 clinical trials plus 3 non-randomized controlled trials in pediatric acute gastroenteritis. B. clausii vs ORT (with or without zinc): shortened diarrhea duration, reduced stool number, shortened hospital stay. Methodologically robust with multiple country populations — among the strongest probiotic evidence bases for pediatric gastroenteritis.

2
PMC7680487 — H. pylori Eradication 130-pt Clinical Trial

Infect Dis — randomized double-blind 130-patient phase IIIB study during H. pylori eradication therapy in Italy. B. clausii 1 capsule three times daily for 2 weeks.

Clinical population described in trial publication.

Infect Dis — randomized double-blind 130-patient phase IIIB study during H. pylori eradication therapy in Italy. B. clausii 1 capsule three times daily for 2 weeks. Week-1 diarrhea incidence 29% vs 48% placebo (RR 0.61, 95% CI 0.39-0.97, p=0.03). 19% absolute risk reduction in adult AAD prevention.

3
PMC8994895 — India Pediatric Phase 3 Clinical Trial

Phase 3 clinical trial in 6-month-to-5-year-old children with acute moderate diarrhea, using ORT + zinc + B. clausii.

Clinical population described in trial publication.

Phase 3 clinical trial in 6-month-to-5-year-old children with acute moderate diarrhea, using ORT + zinc + B. clausii. Indian pediatric population evidence supplementing the global trial base.

Side effects and drug interactions

Common Potential side effects

Generally extremely well-tolerated; spore-forming probiotic with extensive safety record.
Mild GI upset (rare, transient).
Bacteremia in immunocompromised individuals (very rare).
Pregnancy/lactation: limited specific data; consult physician.
Long-term safety: NOAEL >2000 mg/kg (5×10^11 CFU) over 28 days in mice + extensive Italian/Philippine clinical use record.
Allergic reactions (rare).
Industry-sponsorship (Sanofi) — important context for evidence interpretation.

Important Drug interactions

Antibiotics: compatible — intrinsic polyantibiotic resistance allows concurrent dosing (distinguishing advantage).
Most medications: well-tolerated combination profile.
Immunosuppressants: caution (applies to all probiotics).
Other probiotics: compatible.
Anticoagulants: no interactions documented.
PPIs (proton pump inhibitors): compatible — spore-forming probiotic survives gastric environment regardless of pH.

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Frequently asked questions about Bacillus clausii (Enterogermina® / Erceflora)

What is Bacillus clausii?

Bacillus clausii is a spore-forming probiotic commercialized as Enterogermina® (Sanofi/Italy) and Erceflora® in some markets. The spore form is heat-stable and survives stomach acid intact — a distinguishing advantage over lactic acid bacteria probiotics.

What is Bacillus clausii used for?

Bacillus clausii is researched primarily for Gut Health, Immune Support, and Respiratory Health. B. clausii reduces duration and severity of acute diarrhea in children and adults across multiple randomized trials. Effect sizes are moderate; benefits seen within days of starting supplementation.

What is the recommended dosage of Bacillus clausii?

The clinically studied dose is 2 billion spores (2×10⁹ CFU) 2-3 times daily; AAD prevention: 2 billion spores twice daily during antibiotic therapy plus 1 week after. Always follow the product label and check with a healthcare provider for personal advice.

Is Bacillus clausii safe, and does it have side effects?

For most healthy adults, Bacillus clausii is well tolerated at studied doses. Reported effects can include: Generally extremely well-tolerated; spore-forming probiotic with extensive safety record. Mild GI upset (rare, transient). It may also interact with some medications. Bacillus clausii is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Bacillus clausii interact with any medications?

Possible interactions include: Antibiotics: compatible — intrinsic polyantibiotic resistance allows concurrent dosing (distinguishing advantage). Most medications: well-tolerated combination profile. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Bacillus clausii?

NutraSmarts rates the evidence for Bacillus clausii as Strong (4 out of 5). It is backed by 3 clinical trials and 4 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(4 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Sudha MR, Jayanthi N, Pandey DC, Verma AK Bacillus clausii UBBC-07 reduces severity of diarrhoea in children under 5 years of age: a double blind placebo controlled study. Benef Microbes. 2019;10(2):149-154. doi: 10.3920/BM2018.0094.PubMedUsed to support: Double-blind placebo-controlled pediatric RCT showing B. clausii reduced diarrhoea severity/duration. Supports the acute childhood diarrhoea use; benefit is modest and this uses one specific commercial strain (UBBC-07).
  2. Ianiro G, Rizzatti G, Plomer M, Lopetuso L, Scaldaferri F, Franceschi F, et al. Bacillus clausii for the Treatment of Acute Diarrhea in Children: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients. 2018;10(8):1074. doi: 10.3390/nu10081074.PubMedUsed to support: Meta-analysis indicating B. clausii shortens acute diarrhoea in children. Best summary of the main indication, but several included trials are small and industry (Sanofi)-linked.
  3. Nista EC, Candelli M, Cremonini F, Cazzato IA, Zocco MA, Franceschi F, et al. Bacillus clausii therapy to reduce side-effects of anti-Helicobacter pylori treatment: randomized, double-blind, placebo controlled trial. Aliment Pharmacol Ther. 2004;20(10):1181-8. doi: 10.1111/j.1365-2036.2004.02274.x.PubMedUsed to support: RCT showing B. clausii reduced side effects (diarrhoea, nausea) during H. pylori eradication. Supports the adjunct-to-eradication use; modest, symptom-level benefit.
  4. De Castro JA, Kesavelu D, Lahiri KR, Chaijitraruch N, Chongsrisawat V, Jog PP, et al. Recommendations for the adjuvant use of the poly-antibiotic-resistant probiotic Bacillus clausii (O/C, SIN, N/R, T) in acute, chronic, and antibiotic-associated diarrhea in children: consensus from Asian experts. Trop Dis Travel Med Vaccines. 2020;6:21. doi: 10.1186/s40794-020-00120-4.PubMedUsed to support: Expert consensus on adjuvant B. clausii for acute, antibiotic-associated, and chronic pediatric diarrhoea, highlighting its antibiotic-/heat-stable spore properties. Useful context, but a consensus opinion rather than primary trial evidence.