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Probiotic

Saccharomyces boulardii

Also known as: CNCM I-745, Florastor, S. boulardii

A
Evidence

Beneficial yeast probiotic that's antibiotic-resistant. Excellent for diarrhea, C. diff, and antibiotic support.

Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.

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Primary uses

  • Diarrhea
  • Antibiotic support
  • C. diff prevention
  • Traveler's diarrhea

How it works

  • Not killed by antibiotics
  • Secretes anti-toxin factors
  • Supports gut barrier

Dosage

Typical range
250-500 mg (5-10 billion cells) daily
Timing
During and after antibiotics
With food
Either way
Duration
During infection/antibiotics and 2 weeks after
Special populations
Antibiotic users, recurrent C. diff

Forms

  • Capsules

Safety

Common side effects

  • Gas
  • Bloating

Contraindications

  • Central venous catheter
  • Severe immunocompromise

Products containing Saccharomyces boulardii

Top-scoring supplements in our catalog that list Saccharomyces boulardii on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.

Thorne
Sacro-B™
68
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Known interactions

Evidence notes

Strong evidence for diarrhea prevention

Grade A: Multiple well-designed human trials support the main claims.

Cited research for Saccharomyces boulardii

Clinical studies referenced across Formulate guides that mention saccharomyces boulardii. Each links to the full study page with PubMed source + the guides that cite it.

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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.