S. boulardii Side Effects: What Reddit Users Report
About this entry (Saccharomyces boulardii): A probiotic yeast. Because it is a yeast, antibiotics do not kill it.
15 of 478 Reddit owner comments about S. boulardii (3%) describe an unwanted effect. The effects people mention most are gas or bloating. These are self-reports from Reddit IBS and gut communities (November 2025 to October 2026), not a measured side-effect rate, and many people report no problems at all.
Saccharomyces boulardii overall: 4.0 · tolerability 4.8 (higher means fewer unwanted-effect reports).
What people describe
| Effect mentioned | Owner comments |
|---|---|
| Gas or bloating | 4 |
How we counted: among the 15 comments that describe an unwanted effect, a category counts when a sentence names the effect with wording like "gave me" or "made me". Questions and sentences about an effect going away are skipped. One comment can count in more than one row, and keyword counts can include some unrelated mentions, so read the quotes below for context.
Most common complaints
- Side effects: 10 owner comments
- Urgency & loose stools: 3 owner comments
- Regularity: 2 owner comments
- Pain & cramping: 2 owner comments
Safety notes from NIH and published research
- The NIH notes probiotics may not be safe for people who are very ill or have a poorly functioning immune system; ask a doctor first.[NCCIH]
Stop and talk to a doctor if an effect is severe or does not settle. Ask a pharmacist about interactions with any medicine you take.
In their words
4/5 Die-offSide effects“There are probiotics which are fairly safe even with SIBO, s boulardii is one of them, it helped me a lot when I first started it, drink lots of water with it as the yeast is thirsty and you don't want to get constipated (start low so you…”
1/5 Side effects“I tried Florastor as one of the probiotics I tried and it made me significantly worse unfortunately.”
1/5 Side effects“And using random probiotics can promise growth you don't want (I tried Florastor on my own after a round of antibiotics from my GI and it made my methane SIBO worse I think).”
4/5 Die-offGentle“I am also hydrogen dominant SIBO positive and what helped me most was serum-derived bovine immunoglobulins (SBI) and s boulardii (probiotic yeast).”
2/5 Side effectsUrgency & loose stools“Boulardii gave me more diarrhea actually :( I've stoppped taking it as it didn't help me.”
4/5 Bloating & gasSide effects“I took Florastor for a few years and it worked just fine but ever since this happened when I tried Florastor again it just made me more bloated and gassy”
2/5 Side effects“Some people have reported side effects from Florastor and benefits from Jarrows Formulas.”
2/5 Side effects“Boulardii capsule I started getting shakes and anxiety.”
Frequently asked
What side effects do people report with S. boulardii?
15 of 478 Reddit owner comments about S. boulardii (3%) describe an unwanted effect; the ones mentioned most were gas or bloating. These are self-reports, not a measured side-effect rate.
Is S. boulardii safe?
Safety depends on your health and medicines. The NIH and other sources listed on this page note specific cautions. Ask a doctor or pharmacist before starting, especially if you take other medicines or are pregnant.
More on S. boulardii
Compare side-effect reports: Saccharomyces boulardii vs L. rhamnosus GG (Culturelle) · Spore-based probiotics (Bacillus) vs Saccharomyces boulardii · Saccharomyces boulardii vs L. reuteri