Saccharomyces boulardii: What It Is, How It Helps, and What You Need to Know

When your gut feels off—bloating, cramps, or loose stools—you might hear about Saccharomyces boulardii, a beneficial yeast strain used as a probiotic to restore gut balance. Also known as Saccharomyces cerevisiae var. boulardii, it’s not a bacteria like most probiotics—it’s a yeast that survives stomach acid and reaches your intestines alive. That’s why it’s often chosen when antibiotics wipe out good bacteria, or when travel or food poisoning triggers diarrhea.

This yeast works differently than bacterial probiotics. Instead of just adding good bugs, it helps your gut fight off bad ones. It blocks harmful bacteria like C. diff and E. coli from sticking to your intestinal walls. It also boosts your gut’s natural defenses by increasing secretory IgA, a key immune protein in your digestive tract. People use it for antibiotic-associated diarrhea, traveler’s diarrhea, and even chronic gut issues like IBS. Unlike some probiotics, it doesn’t colonize your gut permanently—you take it as needed, and it leaves after a few days.

It’s not a magic pill, but it’s backed by solid research. A 2020 review in the Journal of Clinical Gastroenterology found that Saccharomyces boulardii reduced the risk of antibiotic-related diarrhea by nearly 50% in adults. It’s also been shown to shorten the duration of acute diarrhea in kids. You’ll find it in capsules, powders, and sometimes in combination with other probiotics. But not all products are equal—look for ones that guarantee live cultures through expiration, not just at manufacture.

Some people wonder if it’s safe. For most, yes. But if you have a weakened immune system, a central IV line, or a history of yeast infections, talk to your doctor first. It’s not a treatment for severe infections—it’s a supportive tool. And while it’s often used with antibiotics, you should take it a few hours apart to avoid killing the yeast.

You’ll see it mentioned in posts about gut health, diarrhea recovery, and how lifestyle changes affect medication side effects. It’s not just about popping a pill—it’s about understanding how your gut responds to stress, drugs, and diet. Whether you’re recovering from antibiotics, dealing with frequent stomach bugs, or just trying to keep your digestion steady, Saccharomyces boulardii offers a simple, science-backed option that’s been helping people for decades.