Saccharomyces Boulardii vs Lactobacillus: Which Probiotic Do You Need?
Saccharomyces boulardii is a yeast, so antibiotics don't kill it, and it has good evidence for preventing antibiotic-associated diarrhea. Lactobacillus is a large group of bacteria; specific strains such as L. rhamnosus GG also help with antibiotic diarrhea and have been studied for other gut issues. For a course of antibiotics, S. boulardii is the most convenient choice.
Saccharomyces boulardii vs Lactobacillus is a choice between two very different probiotics: one is a yeast, the other a bacterium. That difference matters for when and how you take them.
Side-by-side
| S. boulardii | Lactobacillus | |
|---|---|---|
| Type | Yeast | Bacteria (many species and strains) |
| Killed by antibiotics | No | Yes, so space doses 2 hours apart |
| Best-studied use | Preventing antibiotic-associated diarrhea | Antibiotic diarrhea (LGG), some IBS and infant colic strains |
| Storage | Often shelf-stable | Some need refrigeration |
| Main safety caution | Immunocompromised, central lines | Immunocompromised, critically ill |
Evidence summary
- A meta-analysis found S. boulardii lowered the risk of antibiotic-associated diarrhea in children and adults.
- L. rhamnosus GG also reduces antibiotic-associated diarrhea, especially in children.
- Other Lactobacillus strains are studied for IBS, infant colic and vaginal health, with mixed results that depend on the strain.
How to choose
- Taking antibiotics? S. boulardii is easy because you don't have to time it around doses. Details in probiotics with antibiotics.
- IBS or bloating? Look for a strain studied for your symptom and try it for 4 weeks.
- Check the label for the full strain name and CFU at expiration.
The verdict
During antibiotics, S. boulardii is the most practical choice. For other gut goals, choose a Lactobacillus strain backed by research for that specific use. Learn more in our probiotics guide.
Frequently asked questions
Can I take both together?
Yes. Some products combine them, and there's no known conflict.
Who should avoid S. boulardii?
People with weakened immune systems or central venous catheters, because rare bloodstream yeast infections have been reported.
Sources
This page is for education and is not a substitute for advice from your doctor. Read our medical disclaimer.