Lactobacillus vs Saccharomyces boulardii: Comparing Probiotic Options
Overview
Lactobacillus and Saccharomyces boulardii are both probiotics used for digestive health, but they’re fundamentally different organisms. Lactobacillus is a bacteria found naturally in the gut and fermented foods, while S. boulardii is a yeast. The key clinical difference: S. boulardii is naturally antibiotic-resistant and can be taken at the same time as antibiotics, while Lactobacillus should be taken hours apart from antibiotic doses.
Quick Comparison
| Feature | Lactobacillus | Saccharomyces boulardii |
|---|---|---|
| Type | Bacteria | Yeast |
| Antibiotic-resistant | No | Yes |
| Timing with antibiotics | 2-3 hours apart | Can take together |
| Colonization | May partially colonize | Does not colonize |
| Best for | General gut health, IBS | Antibiotic-associated diarrhea |
| Common brands | Culturelle, various | Florastor |
Key Difference: Antibiotic Resistance
Lactobacillus:
- Killed by antibiotics
- Must take 2-3 hours apart from antibiotic dose
- Less convenient during antibiotic treatment
- Effect may be reduced during antibiotic use
Saccharomyces boulardii:
- Naturally resistant to ALL antibiotics
- Can take at same time as antibiotic dose
- Simpler dosing schedule
- Full effectiveness during antibiotic treatment
This matters because: The main reason people take probiotics is often during antibiotic treatment. S. boulardii’s resistance makes it more practical and possibly more effective in this setting.
Evidence for Each
Lactobacillus (especially LGG strain):
- Strong evidence for preventing antibiotic-associated diarrhea
- Good evidence for acute infectious diarrhea
- Moderate evidence for IBS symptoms
- Some evidence for general gut health maintenance
Saccharomyces boulardii:
- Strong evidence for preventing antibiotic-associated diarrhea
- Strong evidence for treating acute diarrhea
- Strong evidence for preventing C. difficile
- Good evidence for traveler’s diarrhea
Mechanism Differences
Lactobacillus works by:
- Competing with pathogens for space
- Producing lactic acid (lowers pH)
- Creating antimicrobial substances
- Modulating immune response
- May partially colonize gut
Saccharomyces boulardii works by:
- Breaking down bacterial toxins
- Competing with pathogens
- Supporting gut barrier function
- Anti-inflammatory effects
- Does NOT colonize — transient presence
Dosing Comparison
Lactobacillus:
- 1-50+ billion CFU daily
- Take with meals typically
- Must separate from antibiotic doses (2-3 hours)
- Some products require refrigeration
Saccharomyces boulardii:
- 250-500 mg (about 5-10 billion CFU) daily
- Can take with or without food
- Can take simultaneously with antibiotics
- Usually shelf-stable
Safety Comparison
Both are very safe for most people
Lactobacillus risks:
- Bacteremia (extremely rare, mainly in immunocompromised)
- Mild GI symptoms initially (gas, bloating)
- Generally well-tolerated
Saccharomyces boulardii risks:
- Fungemia (extremely rare, mainly with central lines)
- Do NOT open capsules near central venous catheters
- Generally well-tolerated
Shared cautions:
- Use carefully in severely immunocompromised
- Avoid with central venous catheters (especially S. boulardii)
- Consult provider if critically ill
Best Use Cases
Choose LACTOBACILLUS if:
- General digestive wellness is the goal
- Managing IBS symptoms
- Not currently on antibiotics
- Want potential for colonization
- Prefer bacterial probiotics
Choose SACCHAROMYCES BOULARDII if:
- Currently taking antibiotics
- Want simplest dosing during antibiotic use
- Preventing C. difficile infection
- Traveler’s diarrhea prevention
- Have had antibiotic-associated diarrhea before
Consider BOTH if:
- Want comprehensive probiotic coverage
- Heavy antibiotic use anticipated
- Multiple digestive concerns
- Healthcare provider recommends
During Antibiotic Treatment
Practical comparison:
| Aspect | Lactobacillus | S. boulardii |
|---|---|---|
| When to take | 2-3 hours from antibiotic | With antibiotic (fine) |
| Convenience | More complicated | Simple |
| Effectiveness | May be reduced | Full |
| Typical dose | Continue as directed | Continue as directed |
Example schedule with antibiotics (twice daily):
Lactobacillus:
- 8 AM: Antibiotic
- 11 AM: Lactobacillus
- 8 PM: Antibiotic
- 11 PM: Lactobacillus
S. boulardii:
- 8 AM: Antibiotic + S. boulardii
- 8 PM: Antibiotic + S. boulardii
Speed of Effects
Lactobacillus:
- Prevention effects start immediately (when taking with antibiotics per timing)
- General benefits may take 2-4 weeks
- IBS improvement: 4-8 weeks typically
Saccharomyces boulardii:
- Protective effects begin within hours
- Acute diarrhea improvement: 1-3 days
- Does not build up long-term effects (transient)
Cost Comparison
Both are affordable:
- Lactobacillus: Wide price range depending on product
- S. boulardii: Moderate cost (Florastor is brand-name)
- Generic options available for both
- Neither typically covered by insurance
Combining Them
Using Lactobacillus and S. boulardii together:
- Generally safe
- May provide complementary benefits
- Some products contain both
- Different mechanisms may enhance protection
- Not necessary for most people
When combination might help:
- High-risk antibiotic situations
- History of recurrent C. difficile
- Multiple digestive concerns
- Healthcare provider recommendation
Common Mistakes
With Lactobacillus:
- Taking at same time as antibiotics
- Expecting immediate results for chronic issues
- Using wrong strain for specific condition
- Not storing properly (if refrigeration needed)
With S. boulardii:
- Taking with antifungal medications (defeats purpose)
- Opening capsules near central lines
- Expecting permanent colonization
- Stopping too soon after antibiotics
Special Populations
Pregnancy:
- Both generally considered safe
- Discuss with healthcare provider
- S. boulardii less studied in pregnancy
Children:
- Both used in pediatric populations
- Pediatric products available
- Consult pediatrician
Elderly:
- Both safe for older adults
- No dose adjustments needed
- May be particularly beneficial during antibiotics
Interactions
Lactobacillus:
- Antibiotics reduce effectiveness (timing matters)
- No significant drug interactions otherwise
Saccharomyces boulardii:
- Antifungals will kill it (avoid combination)
- No interaction with antibiotics
- No other significant interactions
Making Your Choice
Summary decision guide:
- Taking antibiotics now? → S. boulardii (simpler, full effect)
- General digestive wellness? → Lactobacillus
- IBS symptoms? → Lactobacillus (LGG or plantarum strains)
- C. difficile concern? → S. boulardii
- Traveling? → S. boulardii
- Long-term maintenance? → Either or both
When to See a Doctor
Consult healthcare provider if:
- Diarrhea persists despite probiotic use
- Blood in stool
- Fever develops
- Severe abdominal pain
- Signs of dehydration
- You’re immunocompromised
- Symptoms worsen
Related Pages
- Lactobacillus Overview
- Saccharomyces boulardii Overview
- Lactobacillus Dosage
- Saccharomyces boulardii Dosage
Sources
- Cochrane reviews on probiotics
- World Gastroenterology Organisation guidelines
- American College of Gastroenterology recommendations
- Comparative effectiveness studies