 The purpose of the present study was to establish the prebiotic effect of a new xylo-oligosaccharides XOS and of an inulin-and-XOS mixture INU-XOS and to determine their effect on endotoxaemia lipopolysaccharides LPS and immune parameters. In this randomized, parallel, placebo-controlled, double-blind study, sixty healthy volunteers were randomly assigned to three groups, receiving either 5 g XOS, INU-XOS 3 g inulin 1 g XOS or an equivalent weight of wheat maltodextrins placebo during 4 weeks. 