Saccharomyces boulardii is a yeast-based probiotic, reports Healthline. It is a species of baker's yeast available as an over-the-counter supplement, states WebMD. Though technically a fungus, it behaves like a probiotic and offers similar benefits.
S. boulardi grows naturally on the skin of lychees and mangosteens, states Florastor, one producer of an S. boulardi product. A yeast-based probiotic possibly supports immune function and intestinal health, as claimed by Health.com. Evidence suggests S. boulardi potentially treats diarrhea, ulcerative colitis and Crohn's disease, according to WebMD. S. boulardi is likely safe for children when taken by mouth appropriately, though diarrhea should be evaluated by a doctor.