Saccharomyces boulardii is a very well-researched probiotic yeast, which has been extensively examined with more than several hundred studies, and has been used in Europe for many decades to treat diarrhoea. It has been recognized as antidiarrhoeals, intestinal antiinflammatory and antiinfective agent.

The clinical activity of S. boulardii is especially relevant in prophylaxis and treatment of intestinal dismicrobism induced by antibiotic and sulphonamides (and disvitaminosis from them), therapy of acute diarrhoea in varied etiology as prophylaxis and treatment of traveler's diarrhoea", therapy of irritable bowel syndrome and treatment of candidiasis stroke intestinal tract.

The Anatomic Therapeutic Chemical Classification indicates S. boulardii as “Antidiarrheal microorganisms” (ATC code: A07FA02).

Studies have shown it may support gut function with many conditions, including food allergies, parasites, Crohn's disease, Candida, Salmonella, travellers diarrhoea, HIV diarrhoea and Pseudomonas, intestinal infections, including Clostridium difficile and Cholera.