Probiotic ·Strong evidence ·Reviewed May 2026
Beneficial probiotic yeast resistant to antibiotics, ideal for gut support during antibiotic use.
The bottom line
Evidence rating strong. Most-documented uses: antibiotic-associated diarrhea, c. difficile prevention, traveler's diarrhea. 18 sources indexed (1993–2025), with 17 interaction records on file.
Core mechanism
Yeast-based probiotic that survives antibiotics. Secretes proteases that degrade Clostridium difficile toxins A and B. Stimulates secretory IgA and anti-inflammatory IL-10.18,9
Can take with or without food; safe during antibiotics3,5
Dosing protocol
Often started with antibiotics and continued briefly after the course is finished.
Ranked by evidence and value.
Real-world pricing across three quality tiers. Assumes Saccharomyces boulardii CNCM I-745.
Assumes 250-500 mg 1-2 times daily. Vendor basis: Florastor/iHerb, Vitacost, NOW, and Amazon marketplace; CNCM I-745 branded products price higher. Updated 2026-05-28.
How much you'd eat to match a supplemental dose.
S. boulardii is a specific probiotic yeast strain; ordinary fermented foods do not reliably contain labeled therapeutic amounts.
Dose: 250-500 mg 1-2 times daily2,4
Timing: Can be taken during antibiotic use
Yeast probiotic, so it is not inactivated by antibacterial antibiotics.
Timing: Start a few days before travel
Use only if you tolerate it well before travel.
What to test, the optimal window inside the conventional range, and how long a response takes.
S. boulardii (250 to 500 mg twice daily) reduces antibiotic-associated diarrhea incidence by roughly 50 percent and may lower calprotectin in active diarrheal illness.2,4
Avoid in central-line patients and severely immunocompromised due to rare fungemia case reports.
Where this appears in the symptom-to-supplement map, ranked by relevance.
This non-pathogenic yeast may shorten the duration of acute and antibiotic-associated diarrhea by competing with pathogens and supporting the gut barrier.1,2
Take a few hours apart from oral antifungal medications, which can inactivate the yeast.
This probiotic yeast is unaffected by antibacterial antibiotics and has good evidence for preventing and shortening antibiotic-associated diarrhea.9,18
Can be taken alongside antibiotics since it resists them; avoid in severely immunocompromised individuals and discuss with a clinician.
This beneficial yeast reduces antibiotic-associated diarrhea during eradication regimens and modestly improves eradication success in pooled trials.3,5
It is a yeast, so it is not killed by antibacterial antibiotics and can be taken concurrently; avoid in severely immunocompromised people or those with central venous catheters.
This probiotic yeast can compete with Candida for adhesion and may modulate gut flora to limit overgrowth, with some supportive trial data.9,16
Useful particularly after antibiotics; avoid in immunocompromised or critically ill patients due to rare fungemia risk.
This probiotic yeast supports the gut barrier and can shorten and firm loose stools, especially when diarrhea is the dominant feature.9,1
Best evidence is in antibiotic-related and infection-related diarrhea; benefit in functional IBS-D is supportive. Avoid in severely immunocompromised people.
This yeast does not colonize permanently and may support gut balance and barrier function without adding to bacterial load.
Often better tolerated than bacterial probiotics in suspected SIBO; avoid in critically ill patients.
Saccharomyces boulardii may support the gut barrier and reduce inflammatory signaling, indirectly aiding permeability in some contexts.1,2
Use caution in critically ill or central-line patients due to rare fungemia reports.
This non-colonizing yeast can help re-establish microbial balance and crowd out opportunistic organisms during disruption.18
Particularly useful after antibiotics or GI infection; avoid in severely immunocompromised individuals.
This non-colonizing yeast supports gut barrier integrity and can help normalize bowel transit, which may ease exertional urgency and diarrhea.
Most evidence is from non-athlete diarrhea contexts; avoid in immunocompromised athletes or those with central venous catheters and check with a clinician first.
This probiotic yeast may support gut flora balance and reduce the bloating or dysbiosis that can contribute to breath odor in some people, but its link to breath is indirect.9,16
Evidence for breath specifically is lacking; it is better studied for digestive regularity. Use caution if immunocompromised or critically ill.
This probiotic yeast may help maintain gut barrier function and reduce antibiotic-associated disruption, relevant after diverticulitis antibiotic courses.9,16
Mainly considered around antibiotic use; avoid in immunocompromised individuals without medical advice.
S. boulardii can help rebalance the gut during or after antibiotic-related GI disruption.1,2
Especially relevant when antibiotics recently preceded the symptoms.
Evidence-based stacks that include it, with the exact dose and timing each one uses.
Saccharomyces Boulardii is a non-colonizing probiotic yeast that may support gut barrier function and help normalize stool patterns, with some trial evidence in diarrhea-predominant and post-infectious IBS. Evidence is still developing and any benefit is likely modest.16,18
Both support gut health but work best at different times. Digestive enzymes work with meals; saccharomyces boulardii prefer an empty stomach or before meals.
Recommendation: Take saccharomyces boulardii 30 min before meals on an empty stomach. Take digestive enzymes at the start of a meal.
Iron supplements can disrupt gut microbiome composition. However, certain probiotic strains may actually enhance iron absorption.
Recommendation: Separate by 2 hours. Some Lactobacillus strains can increase iron absorption, so saccharomyces boulardii may be beneficial for iron-supplementing individuals.
Vitamin D supports the gut immune barrier. Saccharomyces Boulardii modulate the microbiome. Together they support gut-immune axis health.
Recommendation: Complementary gut health support. Vitamin D strengthens gut barrier; saccharomyces boulardii diversify beneficial flora.
Adding the probiotic yeast Saccharomyces boulardii to bacterial probiotics broadens coverage and is particularly effective for preventing antibiotic-associated diarrhea.
Recommendation: Reasonable to combine. Unlike bacterial probiotics, S. boulardii is not killed by antibiotics, so it is a useful companion during antibiotic courses.
L-glutamine and the probiotic yeast Saccharomyces boulardii are often combined for gut barrier and digestive support, acting through complementary mucosal mechanisms.
Recommendation: Reasonable to combine for intestinal support. No timing separation needed.
D-Mannose and the probiotic yeast Saccharomyces boulardii have been combined as a non-antibiotic UTI prophylaxis strategy. A randomized pilot study gave D-Mannose 500 mg plus S. boulardii 3 billion CFU after cystoscopy and reported lower post-procedure UTI incidence and less urinary discomfort versus no treatment. The pairing is mechanistically rational because the two ingredients target distinct steps (urinary bacterial anti-adhesion and flora restoration) and there is no absorption or pharmacological conflict between a poorly metabolized sugar and a transient gut-colonizing yeast.
Recommendation: Reasonable to combine for recurrent UTI prophylaxis. Typical regimens use D-Mannose 1.5 to 2 g once or twice daily with S. boulardii 250 to 500 mg (roughly 3 to 10 billion CFU) daily. No timing separation is required; both can be taken together. Maintain hydration to support urinary flushing. People who are critically ill, immunocompromised, or have a central venous catheter should avoid live S. boulardii because of a rare risk of fungemia.
Saccharomyces boulardii is a yeast probiotic with strong evidence for preventing antibiotic-associated diarrhea and C. difficile infection. Because it is a yeast, S. boulardii is unaffected by antibacterial drugs and can be taken closer to antibiotic doses than bacterial probiotics. It is particularly useful during broad-spectrum antibiotic courses.
Recommendation: Take Saccharomyces boulardii throughout your ciprofloxacin course. Timing flexibility is greater than with bacterial probiotics since it is yeast-based. Continue for at least 1 week after the antibiotic ends.
Saccharomyces boulardii is a yeast probiotic with strong evidence for preventing antibiotic-associated diarrhea, and it is unaffected by metronidazole because it is fungal rather than bacterial. It is particularly useful during anaerobic-targeted therapy.
Recommendation: Take Saccharomyces boulardii throughout your metronidazole course. Timing flexibility is greater than with bacterial probiotics. Continue for at least 1 week after the antibiotic ends.
Saccharomyces boulardii reduces antibiotic-associated diarrhea during clarithromycin therapy and is unaffected by the antibiotic because it is a yeast. It also has supportive evidence for improving H. pylori eradication when added to standard triple therapy.
Recommendation: Take Saccharomyces boulardii throughout your clarithromycin course. Timing flexibility is greater than with bacterial probiotics. Continue for at least 1 week after the antibiotic ends.
Clindamycin carries one of the highest risks of C. difficile-associated colitis among commonly used antibiotics. Saccharomyces boulardii has strong evidence for reducing antibiotic-associated diarrhea and C. difficile infection during high-risk antibiotic exposure. Because it is a yeast, it is unaffected by clindamycin.
Recommendation: Strongly consider taking Saccharomyces boulardii throughout your clindamycin course. Timing flexibility is greater than with bacterial probiotics. Continue for at least 2 weeks after the antibiotic ends.
Saccharomyces boulardii reduces antibiotic-associated diarrhea during amoxicillin therapy and is unaffected by the antibiotic because it is a yeast. It is particularly useful for patients with a history of AAD.
Recommendation: Take Saccharomyces boulardii throughout your amoxicillin course. Timing flexibility is greater than with bacterial probiotics. Continue for at least 1 week after the antibiotic ends.
Saccharomyces boulardii reduces the elevated antibiotic-associated diarrhea risk of amoxicillin-clavulanate. Because it is a yeast, it is unaffected by the antibiotic and timing is less critical than with bacterial probiotics.
Recommendation: Take Saccharomyces boulardii throughout your amoxicillin-clavulanate course. Timing flexibility is greater than with bacterial probiotics. Continue for at least 1 week after the antibiotic ends.
Search all 17 interaction records for Saccharomyces Boulardii →
Numbered references. Citations throughout the page link here.
McFarland LV, Li T. Efficacy and safety of Saccharomyces boulardii CNCM I-745 for the treatment of pediatric acute diarrhea in China: a systematic review and meta-analysis. Frontiers in cellular and infection microbiology. 2025
S. boulardii reduced risk of antibiotic-associated diarrhea from 18.7% to 8.5% (RR: 0.47; 95% CI: 0.38-0.57) across 21 RCTs with 4,780 participants
Szajewska H, Horvath A, Kołodziej M. Systematic review with meta-analysis: Saccharomyces boulardii supplementation and eradication of Helicobacter pylori infection. Alimentary pharmacology & therapeutics. 2015
S. boulardii can be strongly recommended for prevention of antibiotic-associated diarrhea and traveler's diarrhea in adults, and shows promise for IBD
Szajewska H, Horvath A, Piwowarczyk A. Meta-analysis: the effects of Saccharomyces boulardii supplementation on Helicobacter pylori eradication rates and side effects during treatment. Alimentary pharmacology & therapeutics. 2010
Tung JM, Dolovich LR, Lee CH. Prevention of Clostridium difficile infection with Saccharomyces boulardii: a systematic review. Canadian journal of gastroenterology = Journal canadien de gastroenterologie. 2009
Szajewska H, Skórka A, Dylag M. Meta-analysis: Saccharomyces boulardii for treating acute diarrhoea in children. Alimentary pharmacology & therapeutics. 2007
S. boulardii and Lactobacillus showed strongest evidence for preventing AAD; S. boulardii effective for preventing C. difficile recurrence
Chitapanarux T, Wiracha U, Winichakoon P et al.. Efficacy and safety of Saccharomyces boulardii as adjunct therapy with Vancomycin in treating Clostridioides difficile infection: A randomized controlled trial. Scientific reports. 2025
Dezfouli KA, Darban M, Hemmati M et al.. A Randomized, Controlled Study Evaluating Effects of Saccharomyces boulardii in Adult Patients with Asthma. Drug research. 2025
Patients treated with S. boulardii and standard antibiotics had significantly lower relative risk of C. difficile disease recurrence (RR 0.43; 95% CI: 0.20-0.97)
Double-blind placebo-controlled study confirmed S. boulardii effectiveness in preventing traveler's diarrhea
Strong evidence that S. boulardii is safe and has clinically significant benefit in treating acute infectious diarrhea regardless of cause
Case series documents S. boulardii fungemia in critically ill patients, supporting ICU and catheter cautions.
Observational evidence links S. cerevisiae fungemia risk factors with S. boulardii-containing probiotic administration.
This page is educational. Do not start, stop, or change a supplement or medication based on it without checking with a qualified healthcare professional.
Use this with your stack
Add it to your stack, see how it interacts with everything else you take, and get a Stack Score that updates the moment it does.
NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.
NutriStack