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2Corrective

Saccharomyces boulardii

Also sold as S. boulardii, yeast probiotic

Yeast probiotic used in short courses for antibiotic-associated diarrhoea.

2TrustedSupp Tier System™ · Tier 2Take until levels correct
Check before you startThis one has documented interactions with medication classes where the consequences are serious. If you take any prescription medicine, run it past a pharmacist before starting.

How long to take it

Short courses alongside and just after antibiotics.

Who it's actually for

People on antibiotics, and traveller's diarrhoea prevention.

Safe upper limit

Unverified
No formal limit; 250–500 mg twice daily
Should not be used by people who are immunocompromised or have a central venous line — fungaemia has occurred.
No source attached yet. Treat this as a starting point, not a citation, until reviewed.

Interactions to know about

  • ImmunosuppressantsCiclosporin, tacrolimus, azathioprine, biologics, steroids
  • AntibioticsEspecially tetracyclines and quinolones

Other supplements:

Run your full list through the interaction check.

Practical notes

  • Being a yeast, it survives antibiotics — unlike bacterial probiotics.
  • Avoid with a central line or significant immunosuppression.