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Saccharomyces Boulardii supplement
Probiotic Yeast

Saccharomyces Boulardii: Benefits, Dosage, Forms & Research

Probiotic Yeast

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

TL;DR — Quick Answer

S. boulardii is a probiotic yeast that is antibiotic-resistant and clinically proven to prevent antibiotic-associated diarrhea and reduce C. difficile recurrence. A Cochrane review found NNT of 10 for AAD prevention. Standard dose is 250-500mg (5-10 billion CFU) twice daily.

Key Facts

What it is
A non-pathogenic probiotic yeast that is naturally resistant to antibacterial antibiotics
Primary benefits
  • Prevents antibiotic-associated diarrhea (AAD)
  • Reduces C. difficile infection recurrence
  • Treats acute infectious diarrhea in children
  • Supports gut barrier during antibiotic therapy
Typical dosage
250-500mg (5-10 billion CFU) twice daily
Evidence level
Strong
Safety profile
Generally Safe

What the Research Says

S. boulardii has one of the strongest evidence bases among all probiotics. Its unique advantage as a yeast is complete resistance to antibacterial antibiotics, making it the ideal probiotic for concurrent use during antibiotic therapy. Multiple Cochrane and systematic reviews support its use for AAD prevention (NNT=10), C. difficile recurrence prevention, and acute pediatric diarrhea. The WHO recommends it as an adjunct for acute diarrhea management. Its mechanism involves direct toxin degradation, sIgA stimulation, and anti-inflammatory signaling — not competitive exclusion like bacterial probiotics.

Benefits of Saccharomyces Boulardii

  • AAD prevention — a Cochrane review (Szajewska & Kolodziej, 2015, 21 RCTs, n=4,780) found S. boulardii reduced AAD risk by 53% (RR 0.47) with NNT of 10
  • C. difficile prevention — McFarland (2010, meta-analysis, 5 RCTs, n=1,076) showed S. boulardii reduced C. difficile recurrence by 43% when used as adjunctive therapy with antibiotics
  • Acute diarrhea in children — Feizizadeh et al. (2014, meta-analysis, 22 RCTs, n=5,029) found S. boulardii reduced duration of acute diarrhea by approximately 1 day in children
  • Toxin degradation — S. boulardii secretes a 54-kDa serine protease that directly cleaves and inactivates C. difficile toxins A and B (Castagliuolo et al., 1999)
Did you know?

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Forms of Saccharomyces Boulardii

FormBioavailabilityBest For
Lyophilized Capsules (250mg)HighStandard clinical dose — most studied form; each 250mg capsule contains ~5 billion CFU
Sachets/PowderHighPediatric use — can be mixed into food or drinks for children

Dosage Recommendations

General recommendation: 250-500mg (5-10 billion CFU) twice daily

Timing: Can be taken at any time relative to antibiotics (antibiotic-resistant)

Dosage by Condition

ConditionRecommended DoseEvidence
AAD prevention250mg twice daily throughout antibiotic courseStrong
C. difficile recurrence prevention500mg twice daily for 4 weeksStrong
Acute diarrhea (pediatric)250mg twice daily for 5-7 daysStrong

Upper limit: 1,000mg (20 billion CFU) per day

Side Effects and Safety

Safety profile: Generally Safe

Potential Side Effects

  • Very well tolerated; mild gas in some individuals
  • Fungemia risk in immunocompromised patients or those with central venous catheters (rare but serious)
  • Should not be opened near central line patients — airborne yeast can colonize catheters

Drug & Supplement Interactions

  • Antifungals (fluconazole, nystatin) — will kill S. boulardii and negate probiotic benefit
  • Antibacterial antibiotics — no interaction (S. boulardii is a yeast and inherently resistant)
  • Immunosuppressants — use with caution; fungemia risk in severely immunocompromised
Check Saccharomyces Boulardii interactions with other supplements →
BenefitsDosage GuideSide EffectsTypes & FormsResearchFAQ

Related Conditions

Gut Health & Digestion

Related Supplements

Probiotics (Lactobacillus)Probiotics (Bifidobacterium)Probiotics

Frequently Asked Questions

Can I take S. boulardii at the same time as antibiotics?

Yes — this is its primary advantage. S. boulardii is a yeast, so antibacterial antibiotics do not kill it. You can take it at the same time as your antibiotic without spacing doses apart. However, do not take it with antifungal medications like fluconazole, as these will kill the yeast.

How long should I take S. boulardii after finishing antibiotics?

Continue taking S. boulardii for at least 1-2 weeks after completing your antibiotic course. For C. difficile prevention, clinical trials used 4 weeks of supplementation. S. boulardii does not permanently colonize the gut — it washes out within 3-5 days of stopping.

Is S. boulardii safe for children?

Yes. S. boulardii has been extensively studied in pediatric populations and is recommended by the WHO as an adjunct for acute diarrhea in children. Standard pediatric dosing is 250mg twice daily. It is not recommended for premature infants or immunocompromised children.

References

  1. (). Systematic review with meta-analysis: Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea. Alimentary Pharmacology & Therapeutics. DOI
  2. (). Systematic review and meta-analysis of Saccharomyces boulardii in adult patients. World Journal of Gastroenterology. DOI