Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies was asked to provide a scientific opinion on a list of health claims pursuant to Article 13 of Regulation (EC) No 1924/2006. This opinion addresses the scientific substantiation of health claims in relation to fructo-oligosaccharides and decreasing potentially pathogenic gastro-intestinal microorganisms. The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13 health claims and references that EFSA has received from Member States or directly from stakeholders. The food constituent that is the subject of the health claim is fructo-oligosaccharides. The Panel considers that fructo-oligosaccharides are sufficiently characterised in relation to the claimed effect. The claimed effect is ―beneficial effect on intestinal microflora, gut integrity, digestion‖. The target population is assumed to be the general population. The Panel considers that the claimed effect, in the context of decreasing potentially pathogenic gastro-intestinal microorganisms, might be a beneficial physiological effect. No human studies from which conclusions could be drawn for the scientific substantiation of the claim were provided. On the basis of the data presented, the Panel concludes that a cause and effect relationship has not been established between the consumption of fructo-oligosaccharides and decreasing potentially pathogenic gastro-intestinal microorganisms.