Health Guide

Saccharomyces boulardii

What is it?

Saccharomyces boulardii is a yeast used to prevent diarrhea (loose stools) associated with antibiotic use.

Other names for Saccharomyces boulardii include: S boulardii.

Ask your doctor, nurse, or pharmacist if you need more information about this medicine or if any information in this leaflet concerns you.

Before Using:

Tell your doctor if you

  • are taking medicine or are allergic to any medicine (prescription or over-the-counter (OTC) or dietary supplement)
  • are pregnant or plan to become pregnant while using this medicine
  • are breastfeeding
  • have a yeast infection, bowel disease, or low immunity
  • have any other health problems, such as high blood pressure or heart or blood vessel disease


Talk with your caregiver about how much Saccharomyces boulardii you should take. The amount depends on the strength of the medicine and the reason you are taking Saccharomyces boulardii. If you are using this medicine without instructions from your caregiver, follow the directions on the medicine bottle. Do not take more medicine or take it more often than the directions tell you to.

To store this medicine:

Keep all medicine locked up and away from children. Store medicine away from heat and direct light. Do not store your medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down and not work the way it should work. Throw away medicine that is out of date or that you do not need. Never share your medicine with others.


  • Before taking Saccharomyces boulardii, tell your doctor if you are pregnant or breastfeeding
  • You should not take Saccharomyces boulardii if you have a yeast infection (2), a bowel disease (3), or if your immune system is suppressed (low immunity) (3)

Side Effects:

Stop taking your medicine right away and talk to your doctor if you have any of the following side effects. Your medicine may be causing these symptoms which may mean you are allergic to it.

  • Breathing problems or tightness in your throat or chest
  • Chest pain
  • Skin hives, rash, or itchy or swollen skin

Other Side Effects:

You may have the following side effects, but this medicine may also cause other side effects. Tell your doctor if you have side effects that you think are caused by this medicine.

  • You may experience flatulence (gas) and constipation (1)
  • You may have itching or skin eruptions (4)
  • You may develop a yeast infection (1)


1. Fachinformation: Perenterol(R), Saccharomyces boulardii. Thiemann Arzneimittel GmbH, Waltrop, (revised 03/1997), reviewed 3/2000.

2. Lewis SJ & Freedman AR: Review article: The use of biotherapeutic agents in the prevention and treatment of gastrointestinal disease. Aliment Pharmacol Ther 1998; 12:807-822.

3. McFarland LV, Surawicz CM, Greenberg RN et al: Prevention of beta-lactam-associated diarrhea by Saccharomyces boulardii compared with placebo. Am J Gastroenterol 1995; 90(3):439-448.

4. Pletincx M, Legein J & Vandenplas Y: Fungemia with Saccharomyces boulardii in a 1-year-old girl with protracted diarrhea. J Pediatr Gastroenterol Nutr 1995; 21(1):113-115.

Last Updated: 7/4/2018
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites.

All rights reserved