Ther-Biotic® Saccharomyces boulardii

Probiotic yeast formula

4.48 OZ (127 G) POWDER

Benefits and Features

  • Supports healthy intestinal microflora and GI function
  • Promotes healthy bowel transit time.

Detail Overview

This single ingredient Saccharomyces boulardii powder comes with a small, single scoop for measuring accuracy; this clean-label formulation is particularly effective and uniquely convenient for use in high-potency titration protocols. Saccharomyces boulardii is a non-pathogenic, transient yeast. Since its discovery in 1920, clinicians worldwide have used S. boulardii to support normal bowel transit time, promote healthy immune and inflammatory response, and bolster gastrointestinal microbiota diversity, particularly in conjunction with antibiotic therapy. S. boulardii is also commonly used to safely and effectively displace undesirable yeast species, which may play a beneficial role in neurological health, particularly for individuals on the neurodiverse spectrum.

Serving Size 1 Scoop (1 mL or 600 mg) • Servings Per Container 200 scoops
Amount Per Scoop % Daily Value
Saccharomyces boulardii 9 billion CFU
(Approx. 600 mg)
* Daily value not established

Other Ingredients:


Suggested Use

Adults: 1 scoop up to 5 times daily with water, juice, food, or as directed by a healthcare professional. Children: As directed by a healthcare practitioner.

Allergy Statement

Made without of the following common allergens: milk/casein, eggs, fish, shellfish, tree nuts, peanuts, wheat, gluten, soybeans, and sesame. No synthetic colors, flavors, or preservatives. Vegan and non-GMO.


Not recommended for severely immunocompromised individuals or those with central venous catheters. Consult with your physician if you are pregnant or nursing, or have any medical condition, or taking prescription drugs, or under the age of 18 years.


S. boulardii is a unique, non-pathogenic yeast that has been extensively researched and shown to support gastrointestinal health when taken as a dietary supplement.† Klaire Labs™ uses only certified S. boulardii to ensure maximum potency, efficacy, and safety. The Saccharomyces Boulardii powder should be taken with beverages or meals. The powder may be mixed with semi-solid foods such as applesauce or beverages. Avoid the use of hot foods or beverages as this may adversely affect the potency and activity of the supplement.

S. boulardii does not colonize the human intestinal tract and is not one of the microorganisms that normally inhabit the intestines. It is a transient yeast that passes through the intestines after ingestion. S. boulardii does not attach to the mucosal cells lining the intestines, but exerts its beneficial effects on the host as it moves through the gastrointestinal tract.


No, S. boulardii is not S. cerevisiae. S. boulardii is a wild, tropical yeast while S. cerevisiae is commonly known as brewer’s or baker’s yeast. Closely related to S. cerevisiae, S. boulardii is officially classified as Saccharomyces cerevisiae var boulardii Hansen CBS 5926. The 2 species have different genetic makeup and enzyme profiles. Unlike S. cerevisiae, S. boulardii does not make a certain type of reproductive spore called an ascospore and does not use the sugar galactose. It is very resistant to heat and acid and secretes a number of unique physiologically active factors. Only S. boulardii has proven gastrointestinal supportive effects.

No, S. boulardii is completely unrelated to Candida albicans, C. tropicalas, C. krusie, and other Candida species that cause disease and overgrowth in the gastrointestinal and genitourinary tracts. Candida species decrease the acidity of the gastrointestinal mucosal environment, ultimately making the intestinal mucosal membrane susceptible to invasion by potentially harmful bacteria and yeast.

S. boulardii exerts the opposite effect producing lactic and other acids known to inhibit undesirable yeast species. S. boulardii is non-pathogenic (non-disease-causing) and has been shown in numerous clinical trials to be safe and effective.

S. boulardii has been used to positively affect gastrointestinal function in the following situations:

  • support the normal gastrointestinal microbiota during antibiotic use
  • assist individuals with occasional diarrhea
  • favorably modulate the normal gastrointestinal microbiota  
  • assist the body’s natural gastrointestinal detoxification process
  • support host immune defenses and gut barrier function

S. boulardii benefits the gastrointestinal tract in a variety of ways. It produces substances that create an environment that favorably shift the balance of gut microbiota towards more beneficial species. It reduces the ability of undesirable bacteria and yeast to adhere to intestinal cells, thus helping keep these organisms under control. S. boulardii augments gastrointestinal immune responsiveness, stimulates intestinal enzymes that enhance nutrient digestion and absorption, assists in mineral absorption, and helps nourish the colon.

Daily doses ranging from 250 to 1,000 mg taken 1 to 4 times per day have been reported in the medical literature. There is no one standard supplement regimen for S. boulardii. It is prudent to consult a knowledgeable healthcare professional for advice on how much S. boulardii to take and for how long.

S. boulardii is generally used for short-term gastrointestinal support. Often the S. boulardii has been used for up to 2 weeks after a bout of occasional diarrhea has resolved. A common supplement regimen lasts 3 to 4 weeks. 

The Saccharomyces Boulardii capsules and powder should be taken with beverages or meals. If a person cannot swallow the capsules, they may be opened and the contents mixed with semi-solid foods such as applesauce or beverages. Avoid the use of hot foods or beverages as this may adversely affect the potency and activity of the supplement.

Laboratory and clinical testing have demonstrated S. boulardii to be compatible with various lactic acid bacteria including the lactobacilli and bifidobacteria frequently used as probiotic supplements. Clinical studies suggest S. boulardii may work synergistically with other probiotics.

S. boulardii is naturally resistant to all antibacterial antibiotics and can be taken along with antibacterial antibiotics without adversely affecting its potency and efficacy. In fact, several clinical trials have used S. boulardii in conjunction with standard antibiotics and have demonstrated that S. boulardii enhances the success of antibiotic regimen. Additional studies have shown that S. boulardii can be taken along with antibiotics to support the gastrointestinal microbiota.

S. boulardii can be sensitive to a number of commonly prescribed antifungals including nystatin, Diflucan (fluconazole), and Sporonox (itraconazole) and these antifungal agents are known to kill the S. boulardii organisms. If antifungals are prescribed with S. boulardii then both products should be taken at different times. S. boulardii should be taken at least 1 hour before and 2 hours after any antifungal agent.

There is debate within the healthcare community on this issue. However, there are no studies that show natural antifungal therapies such as garlic, grape seed extract, Oregon grape, or berberine affect the potency or actions of S. boulardii. It presently appears that S. boulardii can be taken along with natural antifungals.

There is no known interaction between S. boulardii and prescription medicines except for antifungals. S. boulardii has no adverse interaction with other dietary supplements and can be added to any supplement regimen as needed.

S. boulardii is generally well tolerated however few contraindications exist. People with known allergies to Saccharomyces cervisiae should avoid use of S. boulardii. Currently no clinical studies on the safety of S. boulardii during pregnancy are available. Pregnant women should consult a healthcare professional before use. There have been reports of opportunistic infections in severely immunocompromised patients and in patients with indwelling vascular catheters after supplementation with S. boulardii. In rare cases, people with an indwelling vascular catheter sharing a hospital room with a person taking S. boulardii have developed catheter and blood stream S. boulardii infections. It is likely these catheter and blood infections were related to careless handling of the S. boulardii and poor handwashing by medical staff. S. boulardii should be used with caution in severely immunocompromised patients. People with chronic indwelling vascular catheters should not use S. boulardii.

S. boulardii has been shown to be safe in infants and children. In a clinical trial intended to evaluate the efficacy and safety of S. boulardii in infants and children, 250 mg was administered orally twice daily in 269 children aged 6 months to 14 years. No adverse effects were observed during the course of the study.

Generally, clinical response is considered positive when the number of stools decrease and improvements in stool consistency, from being watery and foul-smelling to more formed and less odorous, are observed. Also lessening of occasional abdominal discomfort or cramping, along with reduction in stool urgency, and restoration of normal bowel movements provides clinical evidence of improvement.

Clinical studies have demonstrated S. boulardii is usually eliminated from the healthy gastrointestinal tract within 6 days after discontinuation of supplementation. Occasionally S. boulardii may be cultured from the stool up to 4 weeks after discontinuing the supplement.

Store in a cool, dry place (59ºF to 85ºF) away from direct light. Keep out of reach of children.

Yes. Klaire Labs™ Saccharomyces Boulardii is free of lactose, casein, gluten, soy, egg, sugar, and maltodextrin. It is safe for use in children and adults following a gluten-free or casein-free diet. Klaire Labs™ Saccharomyces Boulardii contains no artificial additives, colorings, flavoring, or preservatives.