Doc (also known as G.I. Joe Doc) is the code name of two fictional characters from the G.I. Joe: A Real American Hero toyline, comic book and cartoon series by Sunbow/Marvel. The first is Carl W. Greer, who is the G.I. Joe Team's original medic and debuted in 1983. This Doc was born in Concord, Massachusetts. The second fictional character to use the same code name was Carla P. Greer, the niece of the original Doc. She was born in the same city as her uncle, and has the same rank and skills.