Browse/Specialty Dietary Substance
Specialty Dietary Substance

Saccharomyces Boulardii

01 / OVERVIEW

What this compound does

WHAT IT DOES

Saccharomyces boulardii is a friendly yeast that helps keep your gut healthy. When you take it, it travels through your digestive system and helps crowd out harmful bacteria, strengthens the lining of your intestines, and supports your immune system. It's especially helpful for preventing or treating diarrhea caused by antibiotics or infections. This yeast is different from most probiotics because it's not a bacterium, so it isn't killed by antibiotics. It survives stomach acid and works mainly in your intestines. Many people use it to prevent traveler's diarrhea or to recover from stomach bugs. It's generally safe, but people with weakened immune systems should be cautious.

KEY BENEFITS
Reduces antibiotic-associated diarrhea
Helps prevent traveler's diarrhea
Supports recovery from C. difficile infections
Strengthens gut barrier function
Boosts immune response in the digestive tract
BEST FOR
  • • People taking antibiotics who want to avoid diarrhea
  • • Travelers visiting areas with different food and water
  • • Those recovering from a stomach bug or food poisoning
  • • Adults with recurring C. difficile infections
WHAT TO EXPECT

You may notice fewer digestive issues within a few days of starting, especially if you are taking antibiotics. For prevention of traveler's diarrhea, start a few days before travel and continue during the trip. Effects are usually felt within 2-5 days.

WHO SHOULD AVOID THIS
  • • People with weakened immune systems (e.g., organ transplant, HIV, chemotherapy)
  • • Critically ill patients in intensive care
  • • Those with central venous catheters
  • • Infants or very young children without medical advice
MYTHS & FACTS
Myth: Saccharomyces boulardii is a bacterium like most probiotics.
Fact: It is actually a yeast (a fungus), not a bacterium. This is why it is not killed by antibiotics and can be taken alongside them.
Myth: It stays in your gut permanently after you stop taking it.
Fact: S. boulardii is a transient colonizer; it is cleared from the gut within a few days to a week after you stop supplementation.
Myth: It is completely safe for everyone, including those with weak immune systems.
Fact: While generally safe for healthy people, it can cause fungemia in immunocompromised individuals, so those with weakened immune systems should avoid it unless under medical supervision.
At a glance
Typical dose
250–500 mg twice daily (10–20 billion CFU)
Evidence
—
Studies indexed7
How it's made

Production details below.

03 / DOSAGE

How much, when

MAINTENANCE

250–500 mg twice daily (10–20 billion CFU)

Take with or without food; ideally separate from hot beverages; avoid concurrent antifungal use

TIMING

Saccharomyces Boulardii — Any dose

Take with food

02 / EVIDENCE

Peer-reviewed studies

  • PMID: 25910067

    Reduces antibiotic-associated diarrhea

    Meta-analysis of 21 RCTs (n=4780) showed S. boulardii reduced risk of AAD by 47% (RR 0.53, 95% CI 0.44-0.64).

    A
  • PMID: 17446052

    Prevents traveler's diarrhea

    Meta-analysis of 12 RCTs (n=1496) found S. boulardii reduced incidence of traveler's diarrhea by 21% (RR 0.79, 95% CI 0.68-0.91).

    A
  • PMID: 11001015

    Reduces C. difficile recurrence

    RCT (n=168) showed S. boulardii plus standard antibiotics reduced recurrence of C. difficile infection from 24% to 9.5% (p=0.04).

    B
  • PMID: 25910067

    Improves acute childhood diarrhea

    Meta-analysis of 29 RCTs (n=3450) found S. boulardii reduced duration of acute diarrhea by 1.1 days (95% CI 0.8-1.4) and stool frequency on day 2.

    A
  • PMID: 24848764

    Reduces side effects of H. pylori therapy

    Meta-analysis of 11 RCTs (n=2200) showed S. boulardii reduced overall side effects of triple therapy by 42% (RR 0.58, 95% CI 0.48-0.70), especially diarrhea and nausea.

    A
  • PMID: 21315333

    Improves IBS symptoms

    RCT (n=214) found S. boulardii improved overall quality of life and reduced abdominal pain in IBS patients over 4 weeks, but no effect on stool frequency or consistency.

    B
  • PMID: 20601929

    Reduces ventilator-associated pneumonia

    RCT (n=150) in ICU patients showed S. boulardii reduced incidence of VAP from 34.7% to 18.7% (p=0.03), but no effect on mortality.

    B
  • PMID 35727573 · 2022RCT

    Multispecies Probiotic for the Prevention of Antibiotic-Associated Diarrhea in Children: A Randomized Clinical Trial

    B
  • PMID 38613116 · 2024RCT

    Do Herbal Supplements and Probiotics Complement Antibiotics and Diet in the Management of SIBO? A Randomized Clinical Trial

    B
  • PMID 25922398 · 2015Safety Study

    Risk and safety of probiotics

    B
  • PMID 36018495 · 2022Narrative Review

    Bacillus clausii for Gastrointestinal Disorders: A Narrative Literature Review

    B
  • PMID 38659110 · 2024Mechanistic Study

    Dietary supplements: clinical cholesterol-lowering efficacy and potential mechanisms of action

    B
04 / INTERACTIONS

Medicine interactions

  • Immunosuppressants (e.g., prednisone, tacrolimus)· immunosuppressant

    Increased risk of systemic infection (fungemia) due to compromised immune system.

    → Avoid use in immunocompromised patients unless under close medical supervision.

    HIGH

  • Antifungals (e.g., fluconazole, itraconazole)· antifungal

    Antifungals may kill S. boulardii, reducing its efficacy.

    → Separate administration by at least 2-3 hours; monitor for reduced probiotic effect.

    MODERATE

  • Antibiotics (e.g., amoxicillin, ciprofloxacin)· antibiotic

    S. boulardii is resistant to most antibiotics; no direct interaction.

    → Can be taken concurrently to prevent antibiotic-associated diarrhea.

    LOW

  • Oral contraceptives· hormonal_contraceptive

    No known interaction; S. boulardii does not affect estrogen metabolism.

    → No special precautions needed.

    LOW

This page is a reference summary, not a prescription. Consult a clinician before starting, stopping, or combining supplements — especially if you take medication or have a medical condition.