Florastor Dual Action: CNCM I-745 Strain, Dose & Safety

Florastor Dual Action is one of the easier over-the-counter probiotics to evaluate against clinical research because the manufacturer identifies the organism as Saccharomyces boulardii CNCM I-745 rather than stopping at the species name.

That distinction matters. Probiotic effects cannot safely be assumed to transfer from one strain to every other member of the same species.

What is actually in Florastor?

The manufacturer states that each capsule contains 250 mg of S. boulardii CNCM I-745. The adult label uses two capsules per serving and suggests two capsules one to two times daily. Florastor expresses this yeast probiotic in milligrams rather than relying on a CFU marketing comparison.

The product is stored at room temperature. The manufacturer specifically says not to refrigerate it.

Where professional guidance fits

The American Gastroenterological Association’s probiotic guideline lists S. boulardii as one of several probiotic options it suggests for adults and children receiving antibiotics when the goal is prevention of Clostridioides difficile infection.

That is clinically relevant, but it is not the same as saying “AGA recommends Florastor.” The guideline names an organism/formulation category, not a retail brand, and probiotic evidence remains dependent on the strain, preparation, population, dose and outcome.

For an active C. difficile infection, AGA recommends probiotic use only in a clinical-trial context. A probiotic should never delay diagnostic testing or evidence-based treatment for significant antibiotic-associated diarrhea.

Why exact strain identity matters

Academic integrative-medicine guidance from the University of Arizona likewise advises looking for the genus, species and strain, not merely a large CFU number. Florastor discloses CNCM I-745, which makes it possible to ask whether research on that exact strain matches the intended use rather than generalizing from the species name alone.

Important safety limit

Live yeast is not risk-free in every patient. A systematic review of Saccharomyces fungemia reports cases concentrated in medically vulnerable settings, including critical illness. Central venous catheters and severe immune compromise deserve particular caution.

Do not use Florastor if you have a yeast allergy. If you are seriously ill, immunocompromised, hospitalized with complex disease, receiving intensive care or have a central venous catheter, probiotic use belongs with the treating team rather than a self-directed supplement experiment.

Evidence fit and main limitation

The strongest product-level feature is exact strain identity, which makes guideline and trial mapping more defensible than with strain-unresolved S. boulardii products. The limitation is indication scope: antibiotic-related evidence does not validate every digestive-health claim, and the product is not a treatment substitute for active C. difficile infection.

Compare it with Ther-Biotic Saccharomyces boulardii, where the current label does not disclose a strain, and Bio-K+ Advanced Bowel Support, which contains bacterial strains named in AGA guidance but also has an important modern negative trial.

Read the full probiotic and prebiotic evidence guide.