Saccharomyces boulardii is a non-pathogenic yeast strain isolated from the skins of tropical fruits. It has been used worldwide to support intestinal health since its discovery in 1920. It is a transient yeast, meaning it does not colonise the intestinal tract but instead helps to strengthen the gut's natural defences and may also support a reduced inflammatory response. It has been shown to survive the digestive process so it reaches the gut alive and remains in a viable form throughout the bowel.