Johns Hopkins Germ-free Mouse Core Facility is the unique core service to supply germ-free mice for an investigator to study microbiome impact in a variety of fields. The facility is located on the 3rd floor of the Bloomberg School of Public Health and covers about 1400 square feet area. Currently, the core produces 4 strains of mice -- C57BL/6, Rag 1-/-, Min Apc and IL-22 KO and certain technical services, as gavage, injection, fecal pellet collection, etc. Cesarean rederivation to develop germ-free mice is available upon request. Two major types of germ-free experimental set-ups are available: bubble isolators, best suited for longer experiments (>2 weeks) and isocages, individual germ-free cages housing 5 mice each, best suited for short term experiments (< 2 weeks) and those with multiple testing conditions. Consultation on experimental design is available. Cynthia Sears, MD is the director of the core facility. The Core has veterinary care available as needed.