What Is Saccharomyces Boulardii?

Table of ContentsView AllTable of ContentsUsesSide EffectsPrecautionsDosageToxicityInteractionsHow to StoreSimilar SupplementsFrequently Asked QuestionsSources & What to Look For

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View All

Table of Contents

Uses

Side Effects

Precautions

Dosage

Toxicity

Interactions

How to Store

Similar Supplements

Frequently Asked Questions

Sources & What to Look For

Saccharomyces boulardii(S. boulardii) is a probiotic yeast that is a variety ofSaccharomyces cerevisiae(also known as baker’s or brewer’s yeast).It has been isolated from lychee and mangosteen fruit.

The probiotic activity ofS. boulardiiranges from improving gut barrier function, eradicatingpathogens, producing antimicrobialpeptides, stimulating the immune system, and inhibiting inflammation.Specifically,S. boulardiiis used for the prevention and treatment of gastrointestinal tract disorders, including diarrhea symptoms.

This article discusses the uses, side effects, and precautions ofS. boulardii. It also covers what to look for in anS. boulardiisupplement.

Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. Therefore, when possible, choose a supplement that a trusted independent tester, such as USP, ConsumerLabs, or NSF, has tested.However, even if supplements are independently tested, that doesn’t mean they are necessarily safe for all or effective in general. Therefore, it is important to talk to your healthcare provider about any supplements you plan to take and check in about any potential interactions with other supplements or medications.

Dietary supplements are not regulated like drugs in the United States, meaning the Food and Drug Administration (FDA) does not approve them for safety and effectiveness before products are marketed. Therefore, when possible, choose a supplement that a trusted independent tester, such as USP, ConsumerLabs, or NSF, has tested.

However, even if supplements are independently tested, that doesn’t mean they are necessarily safe for all or effective in general. Therefore, it is important to talk to your healthcare provider about any supplements you plan to take and check in about any potential interactions with other supplements or medications.

Supplement FactsActive ingredient(s):Saccharomyces BoulardiiAlternate name(s):Yeast probioticLegal status:Over-the-counter (OTC) dietary supplement (United States)Suggested dose:The optimal dose forS. boulardiihas not been established; doses used in clinical trials tend to be 250 to 500 milligrams (mg) per day in children and not more than 1,000 milligrams (mg) per day in adults.Safety considerations:Pregnancy, breastfeeding, children, older adults, those with digestive tract disease and weakened immune systems, and yeast allergies.Common side effects: bloating, flatulence.Rare but serious side effect: fungal blood infection (in people with multiple serious medical conditions orcentral venous catheters).

Supplement Facts

Active ingredient(s):Saccharomyces BoulardiiAlternate name(s):Yeast probioticLegal status:Over-the-counter (OTC) dietary supplement (United States)Suggested dose:The optimal dose forS. boulardiihas not been established; doses used in clinical trials tend to be 250 to 500 milligrams (mg) per day in children and not more than 1,000 milligrams (mg) per day in adults.Safety considerations:Pregnancy, breastfeeding, children, older adults, those with digestive tract disease and weakened immune systems, and yeast allergies.Common side effects: bloating, flatulence.Rare but serious side effect: fungal blood infection (in people with multiple serious medical conditions orcentral venous catheters).

Uses of Saccharomyces Boulardii

Saccharomyces boulardiiis commonly used for gastrointestinal disorders such as the following:

Other uses ofS. boulardiiinclude the following:

Traveler’s Diarrhea

In a similar study of 3,000 travelers,S. boulardiiwas shown to reduce the incidence of TD dose-dependently (the outcome depended on the dose). Specifically, 39% in the placebo group, 34% in the group given a lower dose ofS. boulardii, and 29% in the group given a higher dose ofS. boulardiideveloped TD. However, the study was limited because only 34%  of the participants completed the study.

Antibiotic-Associated Diarrhea

A systematic review (a collection of studies) showed thatS. boulardiireduced the risk of AAD in people treated with antibiotics from 18.7% to 8.5% compared with placebo or no treatment. The risk of AAD decreased in both adults and children. However, one limitation was that the quality of the included trials varied.More studies may be needed.

Irritable Bowel Syndrome (IBS)

A study of people with irritable bowel syndrome (IBS) usedS. boulardii(9 billion colony-forming units, or CFU, per day) or a placebo for four weeks. The daily number of stools in theS. boulardiigroup decreased, and 87.5% of this group reported improvement in IBS symptoms compared with 72% of the placebo group.However, the sample size of the study was small.

The Best Probiotics for IBS

Crohn’s Disease

A randomized, double-blinded trial conducted on 34 people aged from 19 to 54 years withCrohn’s diseasein remission showed that after three months, theS. boulardiigroup improved the gut barrier function compared to the placebo group.However, the study was limited due to its small sample size.

Ulcerative Colitis

What Are the Side Effects of Saccharomyces Boulardii?

Your provider may recommend you takeS. boulardiifor certain gastrointestinal conditions. However, consuming a supplement likeS. boulardiimay have potential side effects. These side effects may be common or severe.

Common Side Effects

However, common side effects ofS. boulardiiinclude the following:

Severe Side Effects

Seek medical attention if you experience an allergic reaction toS. boulardii.

Caution should be taken if the following apply to you:

Dosage: How Much Saccharomyces Boulardii Should I Take?

Always speak with a healthcare provider before taking a supplement to ensure that the supplement and dosage are appropriate for your needs.

Listed below are the doses ofS. boulardiiused in clinical trials for various conditions:

What Happens If I Take Too Much Saccharomyces Boulardii?

In general, the daily dose ofS. boulardiiis typically greater than 1 billion per day (but no more than 20 billion CFU per day in adults for AAD), and the duration of treatment ranges from seven days to six months.

Unlike other probiotics derived from bacterial strains,S. boulardiihas not developed any antibiotic or antifungal resistance.

It is essential to carefully read a supplement’s ingredient list and nutrition facts panel to know which ingredients and how much of each ingredient is included. Please review this supplement label with your healthcare provider to discuss potential interactions with foods, other supplements, and medications.

How to Store Saccharomyces Boulardii

In addition toS. boulardii, here are some examples of other probiotic supplements:

Similar toS. boulardii, the aforementioned probiotics are used for AAD, IBS, TD, and ulcerative colitis. Specifically,Bacillus coagulans,bifidobacterium(B. bifidum,B. breve, andB. longum), andlactobacillus(L. acidophilus,L. casei,L. plantarum,  andL. rhamnosus) are used for AAD.

For IBS,B. bifidum,B. breve, andB. longumandL. acidophilus,L. plantarum, andL. rhamnosushave been shown to be effective.

Bifidobacterium breve,L. acidophilus, andL. rhamnosushave also been shown to be effective for TD and ulcerative colitis.

To prevent AAD,S. boulardiishould be started early in the course of antibiotic treatment before the change in the gut flora occurs. In clinical trials,S. boulardiiis continued for the duration of antibiotic treatment. However, it is unclear whether prolonged use ofS. boulardiiwould be necessary.

Saccharomyces boulardiican be in either the lyophilized (freeze-dried) or heat-dried forms.Whereas freeze-dried products are stable at room temperature and thus are stored at room temperature, heat-dried products are unstable at room temperature and thus must be refrigerated.

Saccharomyces boulardiican be in either the lyophilized (freeze-dried) or heat-dried forms.

Whereas freeze-dried products are stable at room temperature and thus are stored at room temperature, heat-dried products are unstable at room temperature and thus must be refrigerated.

Due to its natural fungal properties,S. boulardiicannot promote the spread of antimicrobial resistance. On the other hand, bacterial probiotics can contribute to antimicrobial resistance.

However, yeast probiotics do not need to be taken separately from antibiotics because they are intrinsically resistant to antibiotics.

Sources of Saccharomyces Boulardii & What to Look For

Saccharomyces boulardiiis available as a supplement or in liquid beverages along with other probiotics.

The quality and efficacy of probiotic supplements vary from product to product even if the label states that it containsS. boulardiidue to the lower than stated dose or inaccurate strain composition.

Furthermore, a systematic review suggested finding a probiotic product in which the manufacturing company has sponsored original clinical trials. Such a product indicates a degree of commitment that may be absent in other companies that do not sponsor original research.

Food Sources of Saccharomyces Boulardii

Saccharomyces boulardii, in combination with other probiotics, can be found in fermented kombucha tea.

Not only canS. boulardiibe derived from lychee, mangosteen fruit, and kombucha, but it is also derived from dairy products such as kefir.

Saccharomyces Boulardii Supplements

Saccharomyces boulardiiis available in capsules of either lyophilized (freeze-dried) or heat-dried preparations.

The potency or shelf-life of the probiotic product depends on how it is manufactured. For example, heat-dried products, which lose their potency rapidly,  should be refrigerated after opening. Conversely, freeze-dried products ofS. boulardiiare stable at room temperature, provided they are protected from moisture.

Summary

Saccharomyces boulardiiis a yeast probiotic clinically studied for gastrointestinal disorders, including traveler’s diarrhea, antibiotic-associated diarrhea, irritable bowel syndrome, Crohn’s disease, and ulcerative colitis.

In general,S. boulardiiis well-tolerated, but common side effects include bloating, flatulence, and constipation. People with a weakened immune system or who have central venous catheters should not useS. boulardiidue to the risk of fungal infection in the blood.

It would help if you talked with your healthcare provider before takingS. boulardiito ensure it is safe. Tell them about any other conditions and symptoms you have or medications you take.

15 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Lazo-Vélez MA, Serna-Saldívar SO, Rosales-Medina MF, Tinoco-Alvear M, Briones-García M.Application of Saccharomyces cerevisiae var. boulardii in food processing: a review.J Appl Microbiol.2018;125(4):943-951. doi:10.1111/jam.14037Ansari F, Alian Samakkhah S, Bahadori A, et al.Health-promoting properties of Saccharomyces cerevisiae var. boulardii as a probiotic; characteristics, isolation, and applications in dairy products.Crit Rev Food Sci Nutr. 2021;1-29. doi:10.1080/10408398.2021.1949577Pais P, Almeida V, Yılmaz M, Teixeira MC.Saccharomyces boulardii: what makes it tick as successful probiotic?J Fungi (Basel). 2020;6(2):78. doi:10.3390/jof6020078Szajewska H, Kołodziej M.Systematic review with meta-analysis: Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea.Aliment Pharmacol Ther. 2015;42(7):793-801. doi:10.1111/apt.13344National Library of Medicine: MedlinePlus.Saccharomyces boulardii.Rao SSC, Rehman A, Yu S, Andino NM.Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis.Clin Transl Gastroenterol. 2018;9(6):162. doi:10.1038/s41424-018-0030-7Rannikko J, Holmberg V, Karppelin M, et al.Fungemia and Other Fungal Infections Associated with Use of Saccharomyces boulardii Probiotic Supplements.Emerg Infect Dis. 2021;27(8):2090-2096. doi:10.3201/eid2708.210018Ryan JJ, Hanes DA, Schafer MB, Mikolai J, Zwickey H.Effect of the probiotic Saccharomyces boulardii on cholesterol and lipoprotein particles in hypercholesterolemic adults: a single-arm, open-label pilot study.J Altern Complement Med. 2015;21(5):288-293. doi:10.1089/acm.2014.0063Kaźmierczak-Siedlecka K, Ruszkowski J, Fic M, Folwarski M, Makarewicz W.Saccharomyces boulardii CNCM I-745: a non-bacterial microorganism used as probiotic agent in supporting treatment of selected diseases.Curr Microbiol. 2020;77(9):1987-1996. doi:10.1007/s00284-020-02053-9McFarland LV.Systematic review and meta-analysis of Saccharomyces boulardii in adult patients.World J Gastroenterol. 2010;16(18):2202-2222. doi:10.3748/wjg.v16.i18.2202Sivananthan K, Petersen AM.Review of Saccharomyces boulardii as a treatment option in IBD.Immunopharmacol Immunotoxicol. 2018;40(6):465-475. doi:10.1080/08923973.2018.1469143Williams NT.Probiotics.Am J Health Syst Pharm. 2010;67(6):449-458. doi:10.2146/ajhp090168Guo Q, Goldenberg JZ, Humphrey C, El Dib R, Johnston BC.Probiotics for the prevention of pediatric antibiotic-associated diarrhea.Cochrane Database Syst Rev.2019;4(4):CD004827. doi:10.1002/14651858.CD004827.pub5Mourey F, Sureja V, Kheni D, et al.A multicenter, randomized, double-blind, placebo-controlled trial of Saccharomyces boulardii in infants and children with acute diarrhea.Pediatr Infect Dis J. 2020;39(11):e347-e351. doi:10.1097/INF.0000000000002849Wilkins T, Sequoia J.Probiotics for gastrointestinal conditions: a summary of the evidence.Am Fam Physician. 2017;96(3):170-178.

15 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Lazo-Vélez MA, Serna-Saldívar SO, Rosales-Medina MF, Tinoco-Alvear M, Briones-García M.Application of Saccharomyces cerevisiae var. boulardii in food processing: a review.J Appl Microbiol.2018;125(4):943-951. doi:10.1111/jam.14037Ansari F, Alian Samakkhah S, Bahadori A, et al.Health-promoting properties of Saccharomyces cerevisiae var. boulardii as a probiotic; characteristics, isolation, and applications in dairy products.Crit Rev Food Sci Nutr. 2021;1-29. doi:10.1080/10408398.2021.1949577Pais P, Almeida V, Yılmaz M, Teixeira MC.Saccharomyces boulardii: what makes it tick as successful probiotic?J Fungi (Basel). 2020;6(2):78. doi:10.3390/jof6020078Szajewska H, Kołodziej M.Systematic review with meta-analysis: Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea.Aliment Pharmacol Ther. 2015;42(7):793-801. doi:10.1111/apt.13344National Library of Medicine: MedlinePlus.Saccharomyces boulardii.Rao SSC, Rehman A, Yu S, Andino NM.Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis.Clin Transl Gastroenterol. 2018;9(6):162. doi:10.1038/s41424-018-0030-7Rannikko J, Holmberg V, Karppelin M, et al.Fungemia and Other Fungal Infections Associated with Use of Saccharomyces boulardii Probiotic Supplements.Emerg Infect Dis. 2021;27(8):2090-2096. doi:10.3201/eid2708.210018Ryan JJ, Hanes DA, Schafer MB, Mikolai J, Zwickey H.Effect of the probiotic Saccharomyces boulardii on cholesterol and lipoprotein particles in hypercholesterolemic adults: a single-arm, open-label pilot study.J Altern Complement Med. 2015;21(5):288-293. doi:10.1089/acm.2014.0063Kaźmierczak-Siedlecka K, Ruszkowski J, Fic M, Folwarski M, Makarewicz W.Saccharomyces boulardii CNCM I-745: a non-bacterial microorganism used as probiotic agent in supporting treatment of selected diseases.Curr Microbiol. 2020;77(9):1987-1996. doi:10.1007/s00284-020-02053-9McFarland LV.Systematic review and meta-analysis of Saccharomyces boulardii in adult patients.World J Gastroenterol. 2010;16(18):2202-2222. doi:10.3748/wjg.v16.i18.2202Sivananthan K, Petersen AM.Review of Saccharomyces boulardii as a treatment option in IBD.Immunopharmacol Immunotoxicol. 2018;40(6):465-475. doi:10.1080/08923973.2018.1469143Williams NT.Probiotics.Am J Health Syst Pharm. 2010;67(6):449-458. doi:10.2146/ajhp090168Guo Q, Goldenberg JZ, Humphrey C, El Dib R, Johnston BC.Probiotics for the prevention of pediatric antibiotic-associated diarrhea.Cochrane Database Syst Rev.2019;4(4):CD004827. doi:10.1002/14651858.CD004827.pub5Mourey F, Sureja V, Kheni D, et al.A multicenter, randomized, double-blind, placebo-controlled trial of Saccharomyces boulardii in infants and children with acute diarrhea.Pediatr Infect Dis J. 2020;39(11):e347-e351. doi:10.1097/INF.0000000000002849Wilkins T, Sequoia J.Probiotics for gastrointestinal conditions: a summary of the evidence.Am Fam Physician. 2017;96(3):170-178.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Lazo-Vélez MA, Serna-Saldívar SO, Rosales-Medina MF, Tinoco-Alvear M, Briones-García M.Application of Saccharomyces cerevisiae var. boulardii in food processing: a review.J Appl Microbiol.2018;125(4):943-951. doi:10.1111/jam.14037Ansari F, Alian Samakkhah S, Bahadori A, et al.Health-promoting properties of Saccharomyces cerevisiae var. boulardii as a probiotic; characteristics, isolation, and applications in dairy products.Crit Rev Food Sci Nutr. 2021;1-29. doi:10.1080/10408398.2021.1949577Pais P, Almeida V, Yılmaz M, Teixeira MC.Saccharomyces boulardii: what makes it tick as successful probiotic?J Fungi (Basel). 2020;6(2):78. doi:10.3390/jof6020078Szajewska H, Kołodziej M.Systematic review with meta-analysis: Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea.Aliment Pharmacol Ther. 2015;42(7):793-801. doi:10.1111/apt.13344National Library of Medicine: MedlinePlus.Saccharomyces boulardii.Rao SSC, Rehman A, Yu S, Andino NM.Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis.Clin Transl Gastroenterol. 2018;9(6):162. doi:10.1038/s41424-018-0030-7Rannikko J, Holmberg V, Karppelin M, et al.Fungemia and Other Fungal Infections Associated with Use of Saccharomyces boulardii Probiotic Supplements.Emerg Infect Dis. 2021;27(8):2090-2096. doi:10.3201/eid2708.210018Ryan JJ, Hanes DA, Schafer MB, Mikolai J, Zwickey H.Effect of the probiotic Saccharomyces boulardii on cholesterol and lipoprotein particles in hypercholesterolemic adults: a single-arm, open-label pilot study.J Altern Complement Med. 2015;21(5):288-293. doi:10.1089/acm.2014.0063Kaźmierczak-Siedlecka K, Ruszkowski J, Fic M, Folwarski M, Makarewicz W.Saccharomyces boulardii CNCM I-745: a non-bacterial microorganism used as probiotic agent in supporting treatment of selected diseases.Curr Microbiol. 2020;77(9):1987-1996. doi:10.1007/s00284-020-02053-9McFarland LV.Systematic review and meta-analysis of Saccharomyces boulardii in adult patients.World J Gastroenterol. 2010;16(18):2202-2222. doi:10.3748/wjg.v16.i18.2202Sivananthan K, Petersen AM.Review of Saccharomyces boulardii as a treatment option in IBD.Immunopharmacol Immunotoxicol. 2018;40(6):465-475. doi:10.1080/08923973.2018.1469143Williams NT.Probiotics.Am J Health Syst Pharm. 2010;67(6):449-458. doi:10.2146/ajhp090168Guo Q, Goldenberg JZ, Humphrey C, El Dib R, Johnston BC.Probiotics for the prevention of pediatric antibiotic-associated diarrhea.Cochrane Database Syst Rev.2019;4(4):CD004827. doi:10.1002/14651858.CD004827.pub5Mourey F, Sureja V, Kheni D, et al.A multicenter, randomized, double-blind, placebo-controlled trial of Saccharomyces boulardii in infants and children with acute diarrhea.Pediatr Infect Dis J. 2020;39(11):e347-e351. doi:10.1097/INF.0000000000002849Wilkins T, Sequoia J.Probiotics for gastrointestinal conditions: a summary of the evidence.Am Fam Physician. 2017;96(3):170-178.

Lazo-Vélez MA, Serna-Saldívar SO, Rosales-Medina MF, Tinoco-Alvear M, Briones-García M.Application of Saccharomyces cerevisiae var. boulardii in food processing: a review.J Appl Microbiol.2018;125(4):943-951. doi:10.1111/jam.14037

Ansari F, Alian Samakkhah S, Bahadori A, et al.Health-promoting properties of Saccharomyces cerevisiae var. boulardii as a probiotic; characteristics, isolation, and applications in dairy products.Crit Rev Food Sci Nutr. 2021;1-29. doi:10.1080/10408398.2021.1949577

Pais P, Almeida V, Yılmaz M, Teixeira MC.Saccharomyces boulardii: what makes it tick as successful probiotic?J Fungi (Basel). 2020;6(2):78. doi:10.3390/jof6020078

Szajewska H, Kołodziej M.Systematic review with meta-analysis: Saccharomyces boulardii in the prevention of antibiotic-associated diarrhoea.Aliment Pharmacol Ther. 2015;42(7):793-801. doi:10.1111/apt.13344

National Library of Medicine: MedlinePlus.Saccharomyces boulardii.

Rao SSC, Rehman A, Yu S, Andino NM.Brain fogginess, gas and bloating: a link between SIBO, probiotics and metabolic acidosis.Clin Transl Gastroenterol. 2018;9(6):162. doi:10.1038/s41424-018-0030-7

Rannikko J, Holmberg V, Karppelin M, et al.Fungemia and Other Fungal Infections Associated with Use of Saccharomyces boulardii Probiotic Supplements.Emerg Infect Dis. 2021;27(8):2090-2096. doi:10.3201/eid2708.210018

Ryan JJ, Hanes DA, Schafer MB, Mikolai J, Zwickey H.Effect of the probiotic Saccharomyces boulardii on cholesterol and lipoprotein particles in hypercholesterolemic adults: a single-arm, open-label pilot study.J Altern Complement Med. 2015;21(5):288-293. doi:10.1089/acm.2014.0063

Kaźmierczak-Siedlecka K, Ruszkowski J, Fic M, Folwarski M, Makarewicz W.Saccharomyces boulardii CNCM I-745: a non-bacterial microorganism used as probiotic agent in supporting treatment of selected diseases.Curr Microbiol. 2020;77(9):1987-1996. doi:10.1007/s00284-020-02053-9

McFarland LV.Systematic review and meta-analysis of Saccharomyces boulardii in adult patients.World J Gastroenterol. 2010;16(18):2202-2222. doi:10.3748/wjg.v16.i18.2202

Sivananthan K, Petersen AM.Review of Saccharomyces boulardii as a treatment option in IBD.Immunopharmacol Immunotoxicol. 2018;40(6):465-475. doi:10.1080/08923973.2018.1469143

Williams NT.Probiotics.Am J Health Syst Pharm. 2010;67(6):449-458. doi:10.2146/ajhp090168

Guo Q, Goldenberg JZ, Humphrey C, El Dib R, Johnston BC.Probiotics for the prevention of pediatric antibiotic-associated diarrhea.Cochrane Database Syst Rev.2019;4(4):CD004827. doi:10.1002/14651858.CD004827.pub5

Mourey F, Sureja V, Kheni D, et al.A multicenter, randomized, double-blind, placebo-controlled trial of Saccharomyces boulardii in infants and children with acute diarrhea.Pediatr Infect Dis J. 2020;39(11):e347-e351. doi:10.1097/INF.0000000000002849

Wilkins T, Sequoia J.Probiotics for gastrointestinal conditions: a summary of the evidence.Am Fam Physician. 2017;96(3):170-178.

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