Germ free mice represent a model system to study effect of gut microbes on the development of the host gastrointestinal physiology (such as gut barrier function, colonic secretomotor function) and the host immune system (innate and adaptive immune homeostasis). The germ free platform is an essential component of the APC which permits us to study germ-free animals and those colonised with model organisms to understand the molecular mechanisms of host-microbe interactions. More microbes are resident in the distal colon than any other part of the body, and this microbiota has the capacity to influence enteric nerve development, excitability, and gastrointestinal function. Germ-free mice are a valuable tool in interrogating the communication between microbiota and host. The APC Microbiome Institute’s Germ Free Platform is a small unit, staffed by two dedicated technicians and although initially intended for a small number of specific projects, the GF unit is increasingly involved across multiple research projects and is of increasing interest to our industry partners.