The Gnotobiotic Core Facility has been developed to offer Investigators at WashU, as well as at other institutions, access to germ-free mice and the ability to perform experiments associated with manipulation of the microbiota. The current facility is the first step in the initiation of the WashU Gnotobiotic Research, Education and Transgenic (GREaT) facility. The gnotobiotic facility will offer specialized services including rederivation of different mouse lines as germ-free and a wide range of customizable experimental interventions for our investigators. Experiments will enter a queue on a first-come, first-served basis, with consideration given to ensuring access for many investigators.