Saccharomyces boulardii (SB) is an innovative biotherapeutic agent that modulates the gastrointestinal immune response and improves GI integrity. In the GIT, SB increases: the production of secretory IgA, short chain fatty acids and the activity of the brush border disaccharide digestive enzymes. It also inactivates bacterial toxins and reduces digestive inflammatory mediators. SB encourages friendly probiotic bacteria to adhere to and colonise the gastrointestinal tract, supporting micro-ecology. The combination of these actions inhibits the proliferation of unhealthy micro-organisms, while supporting the health of the intestinal environment and strengthening the structure of the epithelial cells in the gut mucosa.