Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to provide a scientific opinion on health claims pursuant to Article 13 of Regulation (EC) No 1924/2006 in the framework of further assessment related to various microorganisms and changes in bowel function, and digestion and absorption of nutrients, decreasing potentially pathogenic gastro-intestinal microorganisms, and stimulation of immunological responses. The food constituents, Bifidobacterium animalis subsp. lactis THT 010801, Bifidobacterium longum subsp. infantis THT 010201, Bifidobacterium longum subsp. longum THT 010301, Bifidobacterium pseudolongum subsp. pseudolongum THT 010501, Lactobacillus casei THT 030401, Lactobacillus gasseri THT 031301, Lactobacillus helveticus THT 031102, Lactobacillus plantarum THT 030701, Lactobacillus plantarum THT 030707, Lactobacillus reuteri THT 030802, Lactobacillus salivarius THT 031001 and Streptococcus thermophilus THT 070102, are sufficiently characterised. The evidence provided did not establish that the proposed claimed effect, stimulation of immunological responses, is a beneficial physiological effect. The references provided for the health claims related to changes in bowel function and decreasing potentially pathogenic gastro-intestinal microorganisms included studies which assessed the effects of food constituents other than the food constituents which are the subject of the claims and/or investigated health outcomes unrelated to the claimed effects. No human studies which investigated the effects of the food constituents on appropriate measures of the claimed effects 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 the food constituents and the claimed effects evaluated in this opinion.