BACKGROUND: Saccharomyces boulardii CNCM I-745 is a probiotic medicinal yeast used in the prevention and treatment of diarrhea. It has numerous effects, i. a. immunological and antitoxin effects, it binds pathogens and has a beneficial effect on the intestinal microbiota. In addition, pronounced trophic effects were detected. METHOD: The focus of this review is on the effects of S. boulardii CNCM I-745 on digestive enzymes located in the brush border membrane. An important role in this context is attributed to polyamines which are synthesized and secreted by S. boulardii CNCM I-745. RESULTS AND CONCLUSIONS: Polyamines are essential for cell proliferation and differentiation. They enhance the expression of intestinal enzymes as well as nutrient transport systems and directly influence the nucleic acid binding capacity. S. boulardii CNCM I-745 induces signals via mitogen-activated protein kinase cascades (MAP kinase pathway) and influences the PI3 kinase signaling pathway. Furthermore, S. boulardii CNCM I-745 secretes certain enzymes that promote nutrient delivery to both the yeast itself and the host organism. The increased presence of digestive enzymes obviously contributes significantly to the clinical effect of S. boulardii CNCM I-745.