Following an application from Lesaffre International/Lesaffre Human Care, submitted pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of France, the Panel on Dietetic Products, Nutrition and Allergies was asked to deliver an opinion on the scientific substantiation of a health claim related to Saccharomyces cerevisiae var. boulardii CNCM I-3799 and reducing gastro-intestinal discomfort. The food constituent that is the subject of the health claim, S. cerevisiae var. boulardii CNCM I-3799, is sufficiently characterised. The claimed effect, reduction of gastro-intestinal discomfort, is a beneficial physiological effect. The target population proposed by the applicant is subjects from 18 to 74 years old with bowel discomfort. The Panel notes that none of the studies provided for the substantiation of the claim was conducted with the strain which is the subject of the claim (S. cerevisiae var. boulardii CNCM I-3799), except for two animal studies and one in vitro study. Upon an EFSA request, the applicant indicated that the rest of the studies provided were conducted with the strain produced by Biocodex Laboratories (S. cerevisiae var. boulardii HANSEN CBS 5926). The applicant also stated that the strain, which is the subject of the claim, S. cerevisiae var. boulardii CNCM I-3799, is equivalent to S. cerevisiae var. boulardii HANSEN CBS 5926, based on a comparative PCR inter-delta element analysis of both strains provided in the application. The Panel considered that the evidence provided was insufficient to establish that the strains S. cerevisiae var. boulardii CNCM I-3799 and HANSEN CBS 5926 are identical and, upon EFSA request for further information, additional evidence was not provided by the applicant. A cause and effect relationship cannot be established between the consumption of S. cerevisiae var. boulardii CNCM I-3799 and reducing gastro-intestinal discomfort.