The Frontier Medics Program was a 23rd century Federation outreach project for non-aligned planets.
History and specifics
The program brought doctors and medical aid to planets located at the Federation border.
In 2271, Drs. Leonard McCoy and Jon Duncan were assigned to a patrol region aboard Joanna. During their tenure with the program, they treated patients at a variety of sites, including the third moon of Omicron Testus IV and planets such as Ophiucus III, Gamma Tarses VII, and Alpha Tau IV. (TOS - Leonard McCoy, Frontier Doctor comics: "Weeds", "Error", "Medics")
In the early 2270s, while acting on behalf of the program, McCoy also cured a plague on Calibus VII. (TOS - Infestation comic: "Issue 1")