Saccharomyces boulardii
A non-pathogenic yeast, making it uniquely resistant to antibacterial antibiotics.
Primary Use Cases
Because it is a fungus, it cannot be killed by standard antibiotics. It is the gold standard for preventing Antibiotic-Associated Diarrhea (AAD) and fighting C. difficile infections.
Dose: 250mg - 500mg daily (CFU is less relevant for yeast, typically dosed in mg).