Saccharomyces boulardii: What It Is, How It Works, and What You Need to Know
When your gut feels off after antibiotics or a bad stomach bug, Saccharomyces boulardii, a non-pathogenic yeast probiotic used to restore healthy gut flora. Also known as S. boulardii, it’s not a bacteria like most probiotics—it’s a yeast that survives stomach acid and works directly in your intestines. Unlike lactobacillus or bifidobacterium, it doesn’t colonize your gut. Instead, it acts like a temporary peacekeeper, calming inflammation, blocking bad bacteria, and helping your natural microbiome bounce back faster.
This yeast is especially useful when your gut gets knocked out of balance. If you’ve taken antibiotics and ended up with antibiotic-associated diarrhea, a common side effect caused by disruption of healthy gut bacteria, S. boulardii has been shown in clinical studies to reduce its severity and duration. It’s also used for traveler’s diarrhea, intestinal distress caused by unfamiliar bacteria in food or water, and even recurring Clostridioides difficile infections, which can be deadly if not managed right. You’ll find it in capsules, powders, and sometimes in combination with other probiotics—but it works best when taken at the right time, usually away from antifungals or hot liquids.
People often ask if it’s safe. Yes, for most. It’s been used for decades in Europe and is now widely available in the U.S. But if you have a central IV line, a weakened immune system, or are critically ill, talk to your doctor first. It’s not a cure-all, but when used correctly, it’s one of the few probiotics with solid clinical backing for specific conditions. You won’t find it in yogurt or kombucha—it’s a specialized supplement designed for targeted gut support.
Below, you’ll find real-world advice on how to use it, what to avoid mixing it with, and how it fits into broader gut health strategies—from managing antibiotic side effects to preventing recurrent infections. These aren’t guesses. They’re based on studies, pharmacist insights, and patient experiences shared in trusted medical guides.
Learn how to space probiotics and antibiotics correctly to prevent diarrhea and protect your gut microbiome. Discover the best strains, doses, and timing based on the latest research.
Dec, 9 2025