Here's a link to some studies about it from aor.


http://www.aor.ca/html/products.php?id=108


And this:

Saccharomyces Boulardii is a non-pathogenic, non-colonizing species of yeast that is clinically recognized for its effectiveness in contending with the symptoms of antibiotic-associated diarrhea (AAD) and Clostridium difficile disease (CDD), which is also incited by Antibiotics . CDD is a leading cause of nosocomial outbreaks of diarrhea and colitis, and saccharomyces boulardii is one of the most widely used and highly regarded probiotics for the treatment of symptoms associated with both AAD and CDD.
While the precise mechanism of action for saccharomyces boulardii remains the subject of conjecture, there are three basic types of explanations - or a combination

thereof. The first involves the ability of saccharomyces boulardii to prevent the gastrointestinal inflammation that causes diarrhea by interfering with the various pathogens that bind to gastrointestinal cells. The second is based on saccharomyces boulardii providing an enhancing effect for certain protective proteins of the immune system whose role is to protect the body from such pathogens. One particular pharmacokinetic theory closely related to this explanation is that saccharomyces boulardii secretes a protease that digests two protein exotoxins which are themselves mediators of inflammatory diarrhea and colitis. The third explanation is that saccharomyces boulardii actually competes with pathogens for receptor sites on the cells of the intestinal walls.

The use of Antibiotics can destroy friendly flora that is essential for the maintenance of optimal intestinal health. Therefore, antiobiotic use can result in an imbalance of naturally occurring yeast and bacteria that would normally be kept in check by this friendly flora. This imbalance can lead to diarrhea. Clostridium difficile is precisely such a bacterium, and is (understandably) extremely difficult to treat with more Antibiotics . In one double-blind, placebo-controlled study of 151 patients who underwent Antibiotic therapy, the rate of patients suffering from antibiotic-associated diarrhea was almost 6 ½ times higher in the placebo group than in the saccharomyces boulardii group.

There is a wealth of other human studies providing testimony to the efficacy of saccharomyces boulardii against various forms of diarrhea, including Traveler's Diarrhea or TD. TD is a major concern for visitors to foreign nations, especially ones where the food and climate are unfamiliar and/or the socioeconomic and hygiene levels are low. One recent clinical review cited saccharomyces boulardii as among the most effective probiotics in treating the symptoms of Traveler's Diarrhea (TD). As a matter of fact, the largest placebo-controlled study of saccharomyces boulardii ever conducted specifically examined its effects on TD. The double-blind study examined 3,000 Austrians who took either a placebo, 250 or 1000 mg of saccharomyces boulardii while they traveled abroad, particularly to North Africa and the near East where recorded incidents of TD were highest. The results showed that those using saccharomyces boulardii suffered ‘significantly fewer' cases of diarrhea than those who took the placebo, and that the beneficial results were dose-dependent.

Recent studies have examined the efficacy of saccharomyces boulardii in treating acute diarrhea in children. A recent review of five clinical trials involving a total of 619 otherwise healthy infants and children with acute gastroenteritis revealed that saccharomyces boulardii ‘significantly reduced' both the risk and the duration of diarrhea.