Comparison guide
Which probiotic: LGG, S. boulardii or a blend?
Probiotic effects are strain-specific, so the strain named on the label matters more than the product category. The best-supported use for all three is preventing antibiotic-associated diarrhoea; for general gut health in healthy people the evidence is weak.
The options, compared
| Option | Evidence | Best for | The honest note | |
|---|---|---|---|---|
| Probiotics | Moderate evidence | Only if it names studied strains | Pooled trials cut antibiotic-associated diarrhoea risk by about 42%, but that support comes mainly from LGG and S. boulardii. A generic blend is not guaranteed to do anything for healthy people. | View |
| Lactobacillus Rhamnosus GG | Moderate evidence | Antibiotic courses, children and adults | Moderate evidence for preventing antibiotic-associated diarrhoea (relative risk around 0.5 at 10–20 billion CFU/day), taken at least 2 hours apart from the antibiotic. A rigorous trial in 971 children found no benefit for acute gastroenteritis. | View |
| Saccharomyces Boulardii | Moderate evidence | Antibiotic courses and H. pylori therapy | The strongest evidence here: 21 RCTs showed it cut antibiotic-associated diarrhoea from about 18.7% to 8.5%, and as a yeast it can be taken alongside antibiotics. Avoid it if you are critically ill, immunosuppressed or have a central line, because of documented fungaemia. | View |
Our verdict
For antibiotic-associated diarrhoea, S. boulardii CNCM I-745 at 250–500 mg twice daily has the best evidence, with LGG a reasonable alternative. Skip generic blends that do not name a studied strain, and skip probiotics altogether if you are severely immunocompromised or critically ill.