Saccharomyces boulardii, or S. boulardii, is an
important probiotic that can recolonize and
sustain flora in the large and small intestine.
Probiotics, as defined by the Food and
Agricultural Organization of the United Nations,
are “live microorganisms which, when
administered in adequate amounts, confer a
health benefit on the host.” (1)
S. boulardii is a strain of yeast, first
discovered in 1920 by French biologist Henri
Boulard while in southeast Asia. Boulard’s
purpose for traveling to the area was to look
for a strain of yeast that would be particularly
heat-resistant for the production of wine. A
cholera outbreak occurred during Boulard’s stay.
Boulard noted that to help combat the diarrhea
associated with the disease, people would either
chew on the skins of lychee and mangosteen
fruits, or boil the skins to make tea. He was
able to isolate the particular substance that
successfully stopped the diarrhea, and
discovered that the yeast could grow at the
unusually high temperature of 98.6 degrees
Fahrenheit. (2) Determining that the yeast was
of the Saccharomyces genus, he named his
discovery after himself. In 1947, Boulard sold
the rights to Saccharomyces boulardii to the
fledgling pharmaceutical company Biocodex. The
company continues to hold the patent to S.
S. boulardii is classified as being non-systemic
and non-pathogenic. It confines itself to the
intestinal tract, instead of spreading
throughout the body. It is popularly marketed in
lyophilized (freeze-dried) form.
Benefits of Saccharomyces boulardii:
Controls Various Forms of Diarrhea
Below are applications of how S. boulardii is
effective in not only the treatment but in the
prevention of a number of diarrhea-related
gastrointestinal disorders. (3)
Decreases Incidence of Acute Diarrhea
Studies conducted in 1994 and 2005 indicate that
the use of S. boulardii versus a placebo shows
efficacy in reducing acute diarrhea in children
and adults. The dose administered to children
age three months and older, as well as to
adults, was 250 mg. twice per day for five days.
Reduces Rate of Recurrence of Pseudomembranous
When administered concurrently with either of
the antibiotics metronidazole or vancomycin, S.
boulardii was found to decrease the likelihood
of additional episodes of pseudomembranous
colitis among people experiencing the disease.
Lessens Bowel Movement Frequency in Irritable
Bowel Syndrome Patients
Research conducted in a series of studies shows
that ingestion of S. boulardii significantly
diminished the number of bowel movements in
people with diarrhea-predominant irritable bowel
syndrome. Use of S. boulardii also improved the
texture of the stool.
Reduces Likelihood of Contracting Travelers’
In 1989, a group of Austrians planning a
worldwide tour participated in a study to
determine the efficacy of S. boulardii in
preventing “travelers’ diarrhea.” They ingested
S. boulardii on a daily basis, five days prior
to departing. It was found that the higher the
dosage, the less likely the tourists were to
develop diarrhea while experiencing food and
water qualities of varying levels. It was also
found that the incidence of diarrhea
corresponded to the locations visited. (7)
Another advantage of using S. boulardii during
travel is that the yeast does not need to be
kept as cold as some other probiotic strains.
Decreases Diarrhea as an Antibiotic Side Effect
Although the primary purpose of antibiotics is
to kill infection-causing bacteria in the body,
they can produce undesirable side effects like
diarrhea, as well as the cramping and nausea
associated with it. When used as a preventative
treatment, S. boulardii has been shown to reduce
the onset, duration and frequency of this side
effect among adults. (8)
Assists in Anti-Inflammatory Protection
When the body is affected by an Escherichia coli
(E. coli) infestation, the proinflammatory
cytokine known as Interleukin 8 has a tendency
to become secreted in the gut. The use of S.
boulardii is seen as beneficial to prevent such
secretions, reducing the severity and toxicity
of the E. coli bacterial invasion. It has been
demonstrated that the effect of the S. boulardii
yeast on E. coli is not to reduce the number of
adherent bacteria produced, but to lower the
number of intracellular bacteria by some 50
Safety of Saccharomyces boulardii:
S. boulardii is generally well tolerated. Side
effects, which are typical of many probiotics,
include flatulence, bloating due to gas,
constipation and increased thirst. These side
effects become less pronounced with regular use
of the yeast. People who are allergic to yeast
should not use S. boulardii. Patients with
severely compromised immune systems should
consult a doctor prior to using S. boulardii
supplements, as there is a possibility of the
development of fungal infections. Infections of
this nature have not been reported among S.
boulardii users with healthy immune systems.
Certain antibiotics may interfere with the
efficacy of probiotics, reducing or obliterating
the bacteria colonies. The yeast should not be
used in concert with anti-diarrhea medications.
(1) FAO/WHO: Health and Nutritional Properties
of Probiotics in Food including Powder Milk with
Live Lactic Acid Bacteria. Report of the Joint
Food and Agriculture Organization (FAO) of the
United Nations/World Health Organization (WHO)
Expert Consultation on Evaluation of Health and
Nutritional Properties of Probiotics in Food
Including Powder Milk with Live Lactic Acid
(2) McFarland L, Bernasconi P (1993).
"Saccharomyces boulardii: a review of an
innovative biotherapeutic agent.” Microbial
Ecology in Health and Disease 6: 157–71.
(3) Vandenplas Y (July 1999). "Bacteria and
yeasts in the treatment of acute and chronic
infectious diarrhea. Part II: Yeasts.” Clinical
Microbiology and Infection. 5 (7): 389–395.
(4) Centina-Sauri G, Sierra Basto G (1994).
"Therapeutic evaluation of Saccharomyces
boulardii in children with acute diarrhea.”
Annale Pediatrie 41: 397–400.
(5) Kurugöl Z, Koturoğlu G (2005). "Effects of
Saccharomyces boulardii in children with acute
diarrhea.” Acta Paediatrica. 94 (1): 44–7.
(6) McFarland L, Surawicz C, Greenberg R (1994).
"A randomised placebo-controlled trial of
Saccharomyces boulardii in combination with
standard antibiotics for Clostridium difficile
disease.” Journal of the American Medical
(7) Kollaritsch H, Kemsner P, Wiedermann G,
Scheiner O (1989). "Prevention of traveler’s
diarrhoea. Comparison of different
non-antibiotic preparations.” Travel Medicine
(8) Kotowska M, Albrecht P, Szajewska H (2005).
"Saccharomyces boulardii in the prevention of
antibiotic-associated diarrhoea in children: a
randomized double-blind placebo-controlled
trial.” Alimentary Pharmacology & Therapeutics.
21 (5): 583-90.
(9) Czerucka D, Dahan S, Mograbi B, Rossi B and
Rampal P (2000). “Saccharomyces boulardii
Preserves the Barrier Function and Modulates the
Signal Transduction Pathway Induced in
Enteropathogenic Escherichia coli-Infected T84
complete description of probiotics, along with
groundbreaking recent clinical research
illustrating the many ways probiotics can
prevent disease, can be found in
Probiotics - Protection Against Infection: Using
Nature's Tiny Warriors To Stem Infection,
This new compendium from one of our own site
contributing authors, Dr. Casey Adams, PhD., takes
the confusion out of selecting and supplementing
with probiotics. Referencing over 500 scientific
studies and reports, and with detailed
instructions on how to make your own probiotic
foods, this book is a must for anyone seeking to
understand the power of probiotics, and improve
their immunity and vitality.
for ordering information.
Discover Which Probiotics Can Help You!
to learn more about this
just released, groundbreaking book.