Probiotics and Medicine Interactions: Immunosuppressants, Antibiotics, Antifungals and Others
What is documented and what is only theoretical about probiotics with immunosuppressants, antibiotics, antifungals and other medicines, and why a pharmacist should check.
Content last updated . This page has not been medically reviewed.
Urgent first
Do not stop or change any prescribed medicine because of anything on this page. If you take medicine to suppress your immune system (for example after a transplant), ask your transplant or prescribing team before using any probiotic. Fever, chills or feeling suddenly very unwell needs prompt care; in the US call 911 for an emergency.Short answer
Few medicine interactions with probiotics are well documented. Most of what exists is laboratory, animal or theoretical. Evidence labels used here: laboratory/animal only, listed in a drug reference (no mechanism or study shown), no interaction shown in the trial and Proper evidence not found.What the sources say
| Medicine group | What the source found | Label |
|---|---|---|
| Immunosuppressants (tacrolimus, everolimus, cyclosporin A) | A 2025 study found Bacillus subtilis TO-A reduced residual tacrolimus and everolimus in a test tube by 8% and 17%, and mice given it had a significant reduction in the maximum blood concentration of tacrolimus. Cyclosporin A was also tested, but the abstract gives no result for it. The authors said caution is needed when tacrolimus and probiotics are given together in humans. [1] | Laboratory/animal only |
| Immunosuppressants, infection risk | Separate from drug levels, weakened immunity raises the risk of harmful effects of probiotics. [2] See bloodstream infection. | Established caution |
| Antibiotics | A drug reference for a yeast probiotic lists antibiotics among medicines that may interact with certain probiotics, without describing how. [3] The 2025 Cochrane review found short-term probiotic use likely not associated with adverse effects in people receiving systemic antibiotics who are not immunocompromised. [4] | Listed in a drug reference; no harm shown in trials |
| Antifungals | The same drug reference lists antifungals (such as clotrimazole, ketoconazole, griseofulvin and nystatin). [3] The mechanism is not described there. | Listed in a drug reference |
| Chemotherapy | Weakened immunity from chemotherapy is among conditions to consult a doctor or pharmacist about before using a yeast probiotic. [3] See cancer treatment cautions. | Established caution |
| Fiber products taken with medicines | MedlinePlus lists some medicines (digoxin, aspirin, nitrofurantoin) not to be taken within 3 hours of psyllium. [5] | Official medicine information |
| Any other medicine (blood thinners, diabetes, thyroid, and others) | Proper evidence not found. We searched PubMed for probiotic drug interactions and for antibiotic timing and viability; only the mouse and laboratory study above was relevant. | None |
Antibiotic timing
Whether bacterial probiotics should be spaced from antibiotic doses, and by how long, is not something we found a trustworthy source for. Proper evidence not found. Search results were consumer pages and were not used. Label directions vary by product: see Probiotic dose and timing. Ask the dispensing pharmacist, who knows your antibiotic. For trial results, see Probiotics for antibiotic-associated diarrhea.Other points
- Surgery. A drug reference advises telling your doctor or dentist about all the products you use before surgery. [3] See Supplements before surgery and Probiotics before surgery and in acute pancreatitis.
- Pregnancy. The same reference says the yeast product should be used in pregnancy only when clearly needed. [3] See Probiotics in pregnancy and breastfeeding.
- Keep a list. The reference advises sharing a list of every product you use with your doctor and pharmacist. [3]
- How interactions work in general: Medication interactions. Overview: Probiotic safety.
Frequently asked questions
Do probiotics interact with antibiotics?
A drug reference lists antibiotics as medicines that may interact with certain probiotics but gives no detail; trials in non-immunocompromised people found short-term use likely not associated with adverse effects. [3][4]
Do probiotics affect immunosuppressant drug levels?
Only laboratory and mouse data were found, for one Bacillus subtilis strain and tacrolimus. Proper evidence not found in people. [1]
Do antifungals affect yeast probiotics?
A drug reference lists antifungals as possible interactions; it does not say how. [3]
Should I stop a medicine if I start a probiotic?
No. Do not start, stop or change a medicine without your doctor's approval. [3]
Who can check my medicines?
Your pharmacist or prescriber, with a full list of everything you take.
References
- Tsuchiya Y, et al. Effect of Probiotics on Immunosuppressive Drug Pharmacokinetics: Interaction between Bacillus subtilis and Tacrolimus in Mice. Biol Pharm Bull. 2025;48(12):1911-1920. Laboratory and mouse study; abstract read 2026-10-22.
- NCCIH (US National Center for Complementary and Integrative Health). Probiotics: Usefulness and Safety. Read 2026-10-22.
- Kaiser Permanente. Drug encyclopedia entry for a Saccharomyces boulardii powder product (generic description). Read 2026-10-22.
- Esmaeilinezhad Z, et al. Probiotics for the prevention of Clostridioides difficile-associated diarrhea in adults and children. Cochrane Database Syst Rev. 2025;9:CD006095. Abstract read 2026-10-22.
- MedlinePlus (US National Library of Medicine). Psyllium. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.