Saccharomyces boulardii

Medically Reviewed on 12/14/2022

Generic Name: Saccharomyces boulardii

Brand and Other Names: Florastor, Florastor Kids, S. boulardii, Saccharomyces boulardii lyo

Drug Class: Herbals

What is Saccharomyces boulardii, and what is it used for?

Saccharomyces boulardii is a probiotic yeast closely related to Saccharomyces cerevisiae, commonly known as brewer’s yeast or baker’s yeast. S. boulardii is used to treat and prevent diarrhea associated with gastrointestinal disorders and antibiotic treatments. Probiotics are beneficial microorganisms that include yeasts, fungi, and bacteria, which inhabit human gut and help in the digestion, breakdown, and absorption of nutrients from the food we eat.

S. boulardii works in many ways to improve gut health, immune function and nutrient absorption, some of which are as follows:

  • Competes with harmful bacteria such as Clostridium difficile and Helicobacter pylori, preventing their growth and promoting the growth of normal bowel flora.
  • Produces enzymes that break down the toxins produced by C. difficile and other pathogens.
  • Enhances innate and acquired immunity and stimulates antibody production against C. difficile toxin A.
  • Maintains the integrity of the intestinal lining and prevents translocation of pathogens.
  • Reduces inflammation by reducing pro-inflammatory activity and promoting anti-inflammatory immune responses.

The suggested uses of S. boulardii include the following:


  • Do not use S. boulardii in patients with yeast allergy.
  • Do not use in patients with hypersensitivity to any of the components of the S. boulardii formulation.
  • Do not use for patients in the following conditions:
    • With central venous catheter
    • In acute care, especially those who require open arterial or venous access
    • Critically ill
    • Severely immunocompromised
    • Before or after organ or bone marrow transplant
  • Some products may contain lactose, use with caution in patients with lactose intolerance.
  • Use with caution in immunocompromised patients. Although rare, there have been reports of fungal blood infection (fungemia) in premature infants.
  • Do not open packets or capsules in the vicinity of patients with central lines, it can get airborne and infect them. Change gloves after handling S. boulardii to avoid accidental transfer into central lines of patients.
  • S. boulardii may have potentially significant interactions with other drugs, and may require frequency and dose adjustments, or monitoring.


Pancreatitis is inflammation of an organ in the abdomen called the pancreas. See Answer

What are the side effects of Saccharomyces boulardii?

Common side effects of Saccharomyces boulardii include:

Call your doctor immediately if you experience any of the following symptoms or serious side effects while using this drug:

This is not a complete list of all side effects or adverse reactions that may occur from the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may also report side effects or health problems to the FDA at 1-800-FDA-1088.

What are the dosages of Saccharomyces boulardii?

There isn’t an established standard dose for Saccharomyces boulardii.

Suggested dosing

  • 1 capsule/packet orally twice a day


  • May swallow capsule whole, or empty contents of capsule or packet onto tongue followed by drinking 4 oz of water or juice
  • May also open capsule or packet and sprinkle over semisolid food (e.g., applesauce, yogurt)
  • Additionally, may open capsule or packet and dissolve contents in liquid and drink (e.g., water, juice, milk)


  • Overdose of Saccharomyces boulardii may cause gas and constipation, which should resolve with discontinuation or dose reduction.

What drugs interact with Saccharomyces boulardii?

Inform your doctor of all medications you are currently taking, who can advise you on any possible drug interactions. Never begin taking, suddenly discontinue, or change the dosage of any medication without your doctor’s recommendation.

  • Saccharomyces boulardii has no known severe interactions with other drugs.
  • Serious interactions of saccharomyces boulardii include:
  • Saccharomyces boulardii has no known moderate or mild interactions with other drugs.

The drug interactions listed above are not all of the possible interactions or adverse effects. For more information on drug interactions, visit the RxList Drug Interaction Checker.

It is important to always tell your doctor, pharmacist, or health care provider of all prescription and over-the-counter medications you use, as well as the dosage for each, and keep a list of the information. Check with your doctor or health care provider if you have any questions about the medication.

Pregnancy and breastfeeding

  • There isn’t enough reliable information on whether taking S. boulardii is safe for pregnant or breastfeeding women, avoid use.
  • Never take any dietary supplement without first checking with your healthcare provider, if you are pregnant or breastfeeding.

What else should I know about Saccharomyces boulardii?

  • Saccharomyces boulardii is possibly safe for most adults if taken in recommended doses for up to 15 months.
  • Take S. boulardii exactly as per label instructions.
  • Check with your healthcare provider before taking any dietary supplement, including S. boulardii.
  • Dietary supplements often contain many ingredients. Check labels for the components in the S. boulardii product you choose.
  • S. boulardii is marketed as a dietary supplement and is not regulated by the FDA. Products may differ in formulations and strengths, and labels may not always match contents; exercise caution in choosing your product.
  • Store S. boulardii safely out of reach of children.
  • In case of overdose and any persistent symptoms, seek medical help or contact Poison Control.

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Saccharomyces boulardii is a probiotic yeast closely related to Saccharomyces cerevisiae, commonly known as brewer’s yeast or baker’s yeast. Saccharomyces boulardii is used to treat and prevent diarrhea associated with gastrointestinal disorders and antibiotic treatments. Common side effects of Saccharomyces boulardii include gas (flatulence), bloating, constipation, and fungal infection in blood (fungemia). Do not take if pregnant. Consult your doctor if breastfeeding.

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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically Reviewed on 12/14/2022