Saccharomyces boulardii is a yeast effective in the management of diarrhea. It is considered a probiotic, a microorganism with beneficial effects on the human digestive tract, and is available both by prescription and over the counter, depending on where patients are receiving care. Like other probiotics, one issue with Saccharomyces boulardii is the risk that some or all of the organisms may be dead in the package, making it hard to determine appropriate doses for patients.
This fungus is closely related to the yeasts used in baking. It appears to be native to the tropics and likes warm environments, making the human digestive tract a good place to cultivate it. People who take Saccharomyces boulardii will retain the yeast in the digestive tract for an extended period of time, and it will not colonize other areas of the body. While in the intestines, it helps balance the natural flora and fauna, making the environment hostile for disease-causing organisms and promoting the growth of beneficial ones.
People with bacterial infections leading to diarrhea generally cannot fight the infection solely with this yeast, but may experience some relief when using it and can find their healing time improved by taking it with antibiotics prescribed to treat the infection. Saccharomyces boulardii appears to work by inhibiting bacterial growth and neutralizing bacterial toxins. These toxins, produced as a byproduct of metabolism, are commonly the culprits behind diarrhea. For patients on antibiotics, the beneficial bacteria that normally keep the gut balanced are wiped out by the medications, leading to digestive problems.
One area where Saccharomyces boulardii has proved very useful is in the management of diarrhea related to antibiotic usage. People who take the organism concurrent with antibiotics tend to experience less disruption of the gastrointestinal tract while on the medications. In addition, it can be helpful for managing diarrhea associated with inflammatory bowel disease, irritable bowel syndrome, and similar issues, although it is not as effective in the management of these conditions as it is with antibiotic-induced diarrhea.
Patients with compromised immune systems need to be careful when taking probiotics. Although this organism is actually recommended to people with diarrhea linked to acquired immune deficiency syndrome (AIDS), high doses of probiotics can be dangerous and may lead to a fungal infection. These patients lack the immune controls to keep the growth of the yeast in check, especially around central lines and ports used to deliver intravenous medication.