Drug & supplement interaction

Saccharomyces Boulardii + Granisetron

Granisetron brand names: Kytril, Sustol.

No Known Interaction

Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated July 2026 · Pair last verified Sep 27, 2026

The bottom line No known interaction

We found no known interaction between Saccharomyces Boulardii and Granisetron in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Granisetron states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Saccharomyces Boulardii and Granisetron

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Granisetron and Saccharomyces Boulardii in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Saccharomyces Boulardii safety at a glance

Saccharomyces Boul... overall Use caution Generally safe for healthy adults but should be avoided by people who are critically ill or immunocompromised.

Pregnancy Use caution Not enough reliable safety data; speak with your doctor before use.

Breastfeeding Use caution Limited safety information is available, so use only with medical advice.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Granisetron and Saccharomyces Boulardii? Ask Dr. Brian Staiger, PharmD, BCPS directly ›

How we checked

Why No Interaction Is Listed for Granisetron

Interactions in our licensed database are recorded against drug classes, not just single drug names. Granisetron is filed under 3 classifications — serotonergic drugs, serotonergic drugs, oral drugs. Saccharomyces Boulardii has documented interactions with 1 drug class — the most serious being antifungals (minor) — and none of Granisetron’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Saccharomyces Boulardii Does Interact With Other Medications

Saccharomyces Boulardii has 40 minor known drug interactions in our database — Granisetron isn’t one of them. If you take anything else, check it against the full list below.

Minor 40 No known interaction 2,790 (incl. Granisetron)

Taking anything else?

Check Another of Your Medications Against Saccharomyces Boulardii

Covers the 2,830 medications we’ve checked against Saccharomyces Boulardii. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Saccharomyces Boulardii and Granisetron May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

Stomach pain / Vomiting / Nausea Additional detail
Saccharomyces Boulardii
“Rarely, oral use of Saccharomyces boulardii has caused gastrointestinal complaints, such as abdominal cramps, flatulence, nausea, vomiting, and decreased appetite.”

Saccharomyces Boulardii · Natural Medicines adverse-effect record, reported in flatulence.
2 sources cited

98731. Flatley EA, Wilde AM, Nailor MD. Saccharomyces boulardii for the prevention of hospital onset Clostridium difficile infection. J Gastrointestin Liver Dis. 2015;24(1):21-4. PubMed

107608. Awoyemi A, Mayerhofer C, Felix AS, et al. Rifaximin or Saccharomyces boulardii in heart failure with reduced ejection fraction: Results from the randomized GutHeart trial. EBioMedicine 2021;70:103511. PubMed
Granisetron

Listed in the ADVERSE REACTIONS section of the FDA label for Granisetron. Read the label on DailyMed ›
Diarrhea Additional detail
Saccharomyces Boulardii
“Rarely, oral use of Saccharomyces boulardii has been associated with fungemia in both immunocompromised and immunocompetent patients. Numerous cases of Saccharomyces fungemia have been reported in critically ill intensive care unit (ICU) patients, particularly those with indwelling or central venous catheters, those receiving enteral feeding, or those receiving broad-spectrum antibiotics.”

Saccharomyces Boulardii · Natural Medicines adverse-effect record, reported in crohn disease.
6 sources cited

1247. Niault M, Thomas F, Prost J, et al. Fungemia due to Saccharomyces species in a patient treated with enteral Saccharomyces boulardii. Clin Infect Dis 1999;28:930.

4357. Pletinex M, Legein J, Vandenplas Y. Fungemia with Saccharomyces boulardii in a 1-year-old girl with protracted diarrhea. J Pediatr Gastroenterol Nutr 1995;21:113-5. DOI

4358. Fredenucci I, Chomarat M, Boucaud C, et al. Saccharomyces boulardii fungemia in a patient receiving ultra-levure therapy. Clin Infect Dis 1998;27:222-3.

4360. Elmer GW, McFarland LV, Surawicz CM, et al. Behaviour of Saccharomyces boulardii in recurrent Clostridium difficile disease patients. Aliment Pharmacol Ther 1999;13:1663-8.

7329. Cesaro S, Chinello P, Rossi L, Zanesco L. Saccharomyces cerevisiae fungemia in a neutropenic patient treated with Saccharomyces boulardii. Support Care Cancer 2000;8:504-5. PubMed

14459. Munoz P, Bouza E, Cuenca-Estrella M, et al. Saccharomyces cerevisiae fungemia: an emerging infectious disease. Clin Infect Dis 2005;40:1625-34. PubMed
Granisetron

Listed in the ADVERSE REACTIONS section of the FDA label for Granisetron. Read the label on DailyMed ›

Reported for Saccharomyces Boulardii but not commonly for Granisetron: reduced appetite, bloating or gas and a higher chance of infection.

Effects for Granisetron come from the ADVERSE REACTIONS section of its FDA label; effects for Saccharomyces Boulardii come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Granisetron Products Have a Food Rule — Saccharomyces Boulardii Should Not Break It

At least one FDA label for a product containing Granisetron says to take it on an empty stomach. Most supplements — Saccharomyces Boulardii included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Granisetron on its own and move Saccharomyces Boulardii to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Granisetron products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

Recommended Dosage ( 2.2 ): The recommended dosage in adults is 10 mg administered as a single subcutaneous injection at least 30 minutes before the start of emetogenic chemotherapy on Day 1.

From the Dosage and Administration section of the FDA label we read for Granisetron — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

From our Q&A

Questions About Saccharomyces Boulardii or Granisetron

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Saccharomyces Boulardii or Granisetron, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Can You Take Multaq With Saccharomyces Boulardii? Answered by Dr. Brian Staiger, PharmD · September 2026 ›

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Granisetron

This page covers Saccharomyces Boulardii only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Granisetron page lists 38 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Lithium (major), 5-htp (moderate), Acetyl-l-carnitine (moderate) and Ayahuasca (moderate).

By severity: 2 major · 25 moderate · 11 minor.

From our pharmacist’s overview on the Granisetron page

“Granisetron (Kytril, Sustol) blocks serotonin signals to stop nausea from chemotherapy and surgery, and this is a list that warrants real caution before you add a supplement to it. Most of the entries raise serotonin themselves, and stacking them on a serotonin-acting drug can push toward serotonin syndrome, a dangerous overload of tha…”

Reviewed by 2 · Jul 18, 2026

Open the Granisetron interaction page

One more smart check

Taking Saccharomyces Boulardii as Part of a Dietary Supplement Product? Check It for Interactions

We hold 608 real supplement products containing Saccharomyces Boulardii, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Saccharomyces Boulardii. Even though Saccharomyces Boulardii itself has no known interaction with Granisetron, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Saccharomyces Boulardii and Granisetron Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Saccharomyces Boulardii

Top 25%

#315 of 1,452 supplements looked up here in the last 7 days

29 days ago today

Medication Granisetron

Steady interest

#1,782 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?

Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Saccharomyces Boulardii reference on this page ↓
Freshness: we automatically re-check this combination every week — this pair was last verified September 27, 2026. The Saccharomyces Boulardii and Granisetron records this page draws on were last updated July 10, 2026.
What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.

Data structure & sourcing designed and verified by Dr. Brian Staiger, PharmD, BCPS.

Supplement

About Saccharomyces Boulardii

What is Saccharomyces Boulardii?

Acute diarrhea
Antibiotic-associated diarrhea
Traveler's diarrhea
Preventing C. difficile recurrence
General gut health

Saccharomyces boulardii is a beneficial yeast used as a probiotic, with the strongest evidence for preventing and treating certain types of diarrhea, including antibiotic-associated diarrhea. It is generally well tolerated in healthy people, but those who are seriously ill or have weakened immune systems should avoid it because of rare but serious bloodstream infections. Talk with your pharmacist or doctor before starting it.

Saccharomyces cerevisiae var. boulardii · Saccharomycetaceae · Whole yeast cells (probiotic microorganism) · Capsules, tablets, powders (often sold as lyophilized/freeze-dried yeast)

An interaction check asks whether these two react with each other — it does not ask whether Saccharomyces Boulardii is a good idea for someone in your situation. Here is what our Saccharomyces Boulardii record says about it on its own.

Saccharomyces Boulardii: dosing

There is no single official standardized dose for S. boulardii. Products are often measured in milligrams of freeze-dried yeast or in colony-forming units (CFU), and amounts vary widely between brands.The best approach is to follow the directions on the product label and to choose a reputable brand.

From our Saccharomyces Boulardii monograph — the full record covers uses, side effects and every documented interaction.

Read the full Saccharomyces Boulardii monograph & all interactions

Medication

About Granisetron

What Is Granisetron Used For?

Brand names: Kytril, Sustol

Granisetron is used to prevent nausea and vomiting linked to emetogenic (nausea-causing) cancer chemotherapy — including high-dose cisplatin — and radiation therapy, including total body irradiation and fractionated abdominal radiation. Granisetron hydrochloride tablets and Granisol oral solution are approved for both the chemotherapy and radiation indications. Sancuso skin patch is approved for prevention of nausea and vomiting in adults receiving moderately and/or highly emetogenic chemotherapy regimens of up to 5 consecutive days.

Granisetron hydrochloride injection (intravenous) is also used to prevent and treat postoperative nausea and vomiting in adults. Sustol (subcutaneous injection) is used in combination with other anti-nausea medicines in adults specifically for the prevention of acute and delayed nausea and vomiting associated with moderately emetogenic chemotherapy or anthracycline and cyclophosphamide combination chemotherapy regimens.

See full Granisetron drug information

Keep checking

Other Drugs & Saccharomyces Boulardii

Browse every other medication we’ve checked against Saccharomyces Boulardii — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major

0Moderate

40Minor

2,789No known interaction

40 Minor 2,789 No interaction

Minor

40 interactions

No interaction 2,789 drugs checked — show the list

We also checked Saccharomyces Boulardii against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,789 medications checked with no known interaction — see the full Saccharomyces Boulardii list.

See the full Saccharomyces Boulardii interactions page

See every supplement checked against Granisetron, ranked by severity

Evidence & sources

Saccharomyces Boulardii References

The 26 references that drive our Saccharomyces Boulardii monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

Niault M, Thomas F, Prost J, et al. Fungemia due to Saccharomyces species in a patient treated with enteral Saccharomyces boulardii. Clin Infect Dis 1999;28:930.
Pletinex M, Legein J, Vandenplas Y. Fungemia with Saccharomyces boulardii in a 1-year-old girl with protracted diarrhea. J Pediatr Gastroenterol Nutr 1995;21:113-5. DOI
Fredenucci I, Chomarat M, Boucaud C, et al. Saccharomyces boulardii fungemia in a patient receiving ultra-levure therapy. Clin Infect Dis 1998;27:222-3.
Elmer GW, McFarland LV, Surawicz CM, et al. Behaviour of Saccharomyces boulardii in recurrent Clostridium difficile disease patients. Aliment Pharmacol Ther 1999;13:1663-8.
Lewis SJ, Freedman AR. Review article: the use of biotherapeutic agents in the prevention and treatment of gastrointestinal disease. Aliment Pharmacol Ther 1998;12:807-22. PubMed
Cesaro S, Chinello P, Rossi L, Zanesco L. Saccharomyces cerevisiae fungemia in a neutropenic patient treated with Saccharomyces boulardii. Support Care Cancer 2000;8:504-5. PubMed
Hennequin C, Thierry A, Richard GF, et al. Microsatellite typing as a new tool for identification of Saccharomyces cerevisiae strains. J Clin Microbiol 2001;39:551-9.
Plein K, Hotz J. Therapeutic effects of Saccharomyces boulardii on mild residual symptoms in a stable phase of Crohn's disease with special respect to chronic diarrhea - a pilot study. Z Gastroenterol 1993;31:129-34.
Borriello SP, Hammes WP, Holzapfel W, et al. Safety of probiotics that contain lactobacilli or bifidobacteria. Clin Infect Dis 2003;36:775-80. PubMed
Marteau P, Seksik P. Tolerance of probiotics and prebiotics. J Clin Gastroenterol 2004;38:S67-9. PubMed
Munoz P, Bouza E, Cuenca-Estrella M, et al. Saccharomyces cerevisiae fungemia: an emerging infectious disease. Clin Infect Dis 2005;40:1625-34. PubMed
Lherm, T., Monet, C., Nougiere, B., Soulier, M., Larbi, D., Le Gall, C., Caen, D., and Malbrunot, C. Seven cases of fungemia with Saccharomyces boulardii in critically ill patients. Intensive Care Med 2002;28(6):797-801. PubMed
Riquelme, A. J., Calvo, M. A., Guzman, A. M., Depix, M. S., Garcia, P., Perez, C., Arrese, M., and Labarca, J. A. Saccharomyces cerevisiae fungemia after Saccharomyces boulardii treatment in immunocompromised patients. J Clin.Gastroenterol. 2003;36(1):41- PubMed
Cherifi, S., Robberecht, J., and Miendje, Y. Saccharomyces cerevisiae fungemia in an elderly patient with Clostridium difficile colitis. Acta Clin Belg. 2004;59(4):223-224. PubMed
Ellouze O, Berthoud V, Mervant M, Parthiot JP, Girard C. Septic shock due to Sacccaromyces boulardii. Med Mal Infect. 2016;46(2):104-105.
Appel-da-Silva MC, Narvaez GA, Perez LRR, Drehmer L, Lewgoy J. Saccharomyces cerevisiae var. boulardii fungemia following probiotic treatment. Med Mycol Case Rep. 2017;18:15-7. PubMed
Atici S, Soysal A, Karadeniz Cerit K, et al. Catheter-related Saccharomyces cerevisiae Fungemia Following Saccharomyces boulardii Probiotic Treatment: In a child in intensive care unit and review of the literature. Med Mycol Case Rep. 2017;15:33-35. PubMed
Martin IW, Tonner R, Trivedi J, et al. Saccharomyces boulardii probiotic-associated fungemia: questioning the safety of this preventive probiotic's use. Diagn Microbiol Infect Dis. 2017;87(3):286-8. PubMed
Romanio MR, Coraine LA, Maielo VP, Abramczyc ML, Souza RL, Oliveira NF. Saccharomyces cerevisiae fungemia in a pediatric patient after treatment with probiotics. Rev Paul Pediatr 2017;35(3):361-4.
Roy U, Jessani LG, Rudramurthy SM, et al. Seven cases of Saccharomyces fungaemia related to use of probiotics. Mycoses 2017;60(6):375-380.
Romanio MR, Coraine LA, Maielo VP, Abramczyc ML, Souza RL, Oliveira NF. Saccharomyces cerevisiae fungemia in a pediatric patient after treatment with probiotics. Rev Paul Pediatr. 2017 Jul-Sep;35(3):361-364. doi: 10.1590/1984-0462/;2017;35;3;00014.
Flatley EA, Wilde AM, Nailor MD. Saccharomyces boulardii for the prevention of hospital onset Clostridium difficile infection. J Gastrointestin Liver Dis. 2015;24(1):21-4. PubMed
Ventoulis I, Sarmourli T, Amoiridou P, et al. Bloodstream infection by Saccharomyces cerevisiae in two COVID-19 patients after receiving supplementation of Saccharomyces in the ICU. J Fungi (Basel). 2020;6(3):98. PubMed
Wombwell E, Bransteitter B, Gillen LR. Incidence of Saccharomyces cerevisiae fungemia in hospitalised patients administered Saccharomyces boulardii probiotic. Mycoses 2021;64(12):1521-1526.
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):2090-6.
Awoyemi A, Mayerhofer C, Felix AS, et al. Rifaximin or Saccharomyces boulardii in heart failure with reduced ejection fraction: Results from the randomized GutHeart trial. EBioMedicine 2021;70:103511. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Saccharomyces Boulardii and Granisetron Together: Common Questions

Is it safe to take Saccharomyces Boulardii with Granisetron?

We do not list a known interaction between Saccharomyces Boulardii and Granisetron. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.

Do Saccharomyces Boulardii and Granisetron have any of the same side effects?

Yes — our sources link each of them separately to 4 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.

Should I take Saccharomyces Boulardii and Granisetron at the same time of day?

At least one FDA label for a product containing Granisetron says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Granisetron on its own and move Saccharomyces Boulardii to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.

How was the Saccharomyces Boulardii and Granisetron combination checked?

Interactions in our licensed database are recorded against drug classes. Granisetron is filed under 3 classifications, and Saccharomyces Boulardii has documented interactions with 1 drug class — none of Granisetron's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.

Does Saccharomyces Boulardii interact with any other medications?

Yes. Saccharomyces Boulardii has 40 documented drug interactions in our database — Granisetron is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.

Does Granisetron interact with any supplements?

Yes. Granisetron has documented interactions with 38 supplements in our database — Saccharomyces Boulardii is not one of them. The Granisetron interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Saccharomyces Boulardii monograph Uses, safety profile, and every drug interaction in one place Granisetron drug information The full plain-English guide to this medication Granisetron supplement interactions Every supplement checked against Granisetron, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 26 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Granisetron and Saccharomyces Boulardii?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.