Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies was asked to provide a scientific opinion on health claims pursuant to Article 13.1 of Regulation (EC) No 1924/2006 in the framework of further assessment related to Saccharomyces boulardii ATY-SB-101 and the following claimed effects: "maintains and restores the natural flora" and "modulating both innate and adaptive host immunity to respond against pathogen infection". The food constituent that is the subject of the claims, Saccharomyces boulardii ATY-SB-101 (BCCM/MUCL 53837), is not sufficiently characterised. On the basis of the data presented, the Panel concludes that a cause and effect relationship cannot be established between the consumption of Saccharomyces boulardii ATY-SB-101 (BCCM/MUCL 53837) and the proposed claimed effects.