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Saccharomyces boulardii Dosage: How Much and When to Take

Last reviewed: December 2025

Overview

Saccharomyces boulardii is typically dosed at 250-500 mg (approximately 5-10 billion CFU) once or twice daily. Unlike bacterial probiotics, it can be taken at the same time as antibiotics because it’s naturally antibiotic-resistant. The specific dose depends on the condition being treated.

Standard Dosing

Typical adult doses:

  • Prevention: 250-500 mg once or twice daily
  • Treatment: 250-500 mg twice daily
  • Most products contain approximately 5 billion CFU per 250 mg

Common regimens:

  • Florastor: 250 mg twice daily (standard)
  • Some products: 500 mg once daily
  • Higher doses used in some clinical studies

Dosing by Condition

Antibiotic-associated diarrhea prevention:

  • 250 mg twice daily OR 500 mg once daily
  • Start when antibiotics begin
  • Continue for 1-2 weeks after antibiotics end
  • Can take at same time as antibiotic doses

Traveler’s diarrhea prevention:

  • 250 mg twice daily
  • Start a few days before travel
  • Continue throughout trip
  • Continue for several days after returning

Acute infectious diarrhea:

  • 250-500 mg twice daily
  • Continue until symptoms resolve
  • Plus additional 1-2 days
  • Stay hydrated alongside treatment

C. difficile prevention/recurrence:

  • 250-500 mg twice daily
  • Used alongside prescribed antibiotics for C. diff
  • Continue 4 weeks after antibiotic completion
  • Medical supervision recommended

H. pylori treatment support:

  • 250 mg twice daily
  • Taken with standard triple or quadruple therapy
  • May reduce antibiotic side effects
  • Continue through antibiotic course

How to Take

Timing:

  • Can take with or without food
  • Can take at same time as antibiotics (major advantage)
  • Consistency in timing helps establish routine
  • Once or twice daily depending on product/indication

With antibiotics — no separation needed:

  • S. boulardii is a yeast, not bacteria
  • Antibiotics don’t affect it
  • Can swallow together with antibiotic dose
  • Simplifies medication schedule

Administration:

  • Swallow capsules whole with water
  • Powder can be mixed with cool or room temperature liquid
  • Don’t use hot beverages (kills the yeast)
  • Chewables should be chewed thoroughly

Age-Specific Dosing

Adults:

  • Standard: 250-500 mg once or twice daily
  • Up to 1000 mg daily in some studies
  • Follow product recommendations

Children (age 3+):

  • Florastor Kids: 250 mg once or twice daily
  • Pediatric products available
  • Powder or chewable forms easier

Infants and toddlers:

  • Consult pediatrician
  • Lower doses may be used
  • Mix powder with formula, breast milk, or food
  • Usually 250 mg daily or less

Elderly:

  • No dose adjustment needed
  • Same as adult dosing
  • May benefit particularly during antibiotic use

Duration of Use

Short-term use:

  • During antibiotic courses
  • Traveler’s diarrhea prevention (during trip)
  • Acute diarrhea episodes
  • Usually 1-4 weeks

Extended use:

  • C. difficile recurrence prevention: 4+ weeks after antibiotics
  • Some chronic digestive conditions
  • Long-term use appears safe
  • Discuss with healthcare provider

When to stop:

  • After completing antibiotic course + 1-2 weeks
  • When traveling is complete
  • When acute symptoms resolve
  • Per healthcare provider guidance

Timing Relative to Antibiotics

Key advantage of S. boulardii:

Probiotic TypeTiming with Antibiotics
Bacterial (Lactobacillus, etc.)Must take 2-3 hours apart
Saccharomyces boulardiiCan take together

This makes S. boulardii more convenient during antibiotic treatment.

What If You Miss a Dose?

If you forget:

  • Take when you remember
  • If almost time for next dose, skip the missed one
  • Don’t double up on doses
  • Return to regular schedule

Occasional misses:

  • Generally not problematic
  • Consistent use is better
  • Return to routine as soon as possible

Product Selection

What to look for:

  • Specific strain name (S. boulardii CNCM I-745 or lyo)
  • CFU count guaranteed at expiration
  • Reputable manufacturer
  • Appropriate form for your needs

Popular products:

  • Florastor (CNCM I-745 strain — most studied)
  • Generic S. boulardii products
  • Combination products with other probiotics

Storage

Most products:

  • Shelf-stable at room temperature
  • Store in cool, dry place
  • Keep away from heat and moisture
  • Check expiration dates

Unlike bacterial probiotics:

  • Refrigeration usually not required
  • More stable at room temperature
  • Good for travel

Combining with Other Probiotics

Taking with bacterial probiotics:

  • Generally safe to combine
  • Some products contain both
  • Different mechanisms may complement
  • Not necessary but not harmful

Considerations:

  • May be redundant for same indication
  • Each has specific evidence base
  • S. boulardii preferred during antibiotics (resistance advantage)
  • Discuss with healthcare provider if uncertain

Sources

  • Clinical dosing studies
  • Florastor prescribing information
  • Gastroenterology guidelines
  • Systematic reviews on probiotic dosing
Last reviewed: December 2025