Following an application from Danone Produits Frais France submitted pursuant to Article 14 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 a fermented milk drink Actimel® containing Lactobacillus casei (Lc) DN-114 001 and reduction of the presence of Clostridium difficile toxins in the gut which reduces the incidence of acute diarrhoea. The Panel considers that the food constituent, Actimel®, which is the subject of the health claim, is sufficiently characterised. The Panel considers that reducing the risk of Clostridium difficile diarrhoea by reducing the presence of C. difficile toxins is a beneficial physiological effect. In total the applicant indicated seven publications on human studies, three unpublished human studies, eight published and one unpublished non-human studies to be pertinent for the claimed effect. In weighing the evidence, the Panel took into account that human and animal studies showed partial survival of Lc DN-114 001 during its gastrointestinal passage, that one human intervention study with Actimel® which showed a statistically significant risk reduction for CDAD had considerable limitations, that there were only limited data on the effect of Actimel® on the reduction C. difficile toxins (the risk factor) in humans, that one study which showed an inhibitory effect of Lc DN-114 001 on the growth of C. difficile in vitro does not predict the occurrence of an effect against C. difficile in humans, that five further human studies do not support the proposed mechanisms by which Actimel® could exert the claimed effect, and that the evidence provided from a further two animal and three in vitro studies does not establish that effects of Actimel® or Lc DN-114 001 in these model systems related to immune function and infection can predict the occurrence of such effects in humans. The Panel concludes that the evidence provided is insufficient to establish a cause and effect relationship between the consumption of Actimel® and a reduction of the risk of C. difficile diarrhoea by reducing the presence of C. difficile toxins.