The medical authority of Starfleet, overseeing health regulations, research and the doctors who serve on ships and stations.
Starfleet Medical is the branch of Starfleet responsible for medical research, health regulations and the doctors and nurses who serve aboard ships and stations. Its headquarters is on Earth, and its rulings on quarantine, treatment and fitness for duty bind Starfleet crews.
Beverly Crusher leaves the Enterprise during the second season of The Next Generation to head Starfleet Medical for a year before returning to her post. Julian Bashir trains at Starfleet Medical before his assignment to Deep Space Nine, graduating near the top of his class.