Quick Answer: A M.A.S.H., or Mobile Army Surgical Hospital, is a field medical unit tasked with helping soldiers and civilians recover from injuries sustained during a war. The movie MASH and its spin-off television show M*A*S*H follow the fictional 4077th, a medical unit serving during the Korean War. The doctors at the M.A.S.H. 4077 do everything they can to keep people alive, using humor as a means of dealing with the gruesome realities of the war.

A M.A.S.H., or Mobile Army Surgical Hospital, is a field medical unit tasked with helping soldiers and civilians recover from injuries sustained during a war.

8209th M.A.S.H., Korea, August 1952

The movie MASH (1970) and television show M*A*S*H (1972 - 1983) follow the fictional 4077th, a medical unit serving during the Korean War. Both the film and television show are based on the book MASH: A Novel about Three Army Doctors by Richard Hooker (1968), which is based on his experiences as a surgeon with the 8055th during the Korean War. The television show is often seen as an allegory for the Vietnam War, which was still in progress when the show began. As such, much of the show questioned and mocked the United States’ involvement in the war under the protection of its comedic tone.

Richard Hooker at the original Swamp, 8055th M.A.S.H., Korea

Wayne Rogers as Trapper John and Alan Alda as Hawkeye in M*A*S*H

The show and movie focus on the antics of the wisecracking, alcoholic, womanizing surgeon Captain Benjamin Franklin “Hawkeye” Pierce (Donald Sutherland in the film and Alan Alda on the show) as he interacts with other surgical staff, members of the military and patients.

Larry Linville, Loretta Swit, Alan Alda, McLean Stevenson, Wayne Rogers, William Christopher, Gary Burghoff and Jamie Farr in M*A*S*H

Elliott Gould, Robert Duvall and Donald Sutherland in MASH

More often than not, both the film and the show portray civilian surgeon Hawkeye at odds with “regular army” head-nurse Major Margaret “Hot Lips” Houlihan (Sally Kellerman; Loretta Swit) and surgeon Major Frank Burns (Robert Duvall; Larry Linville).

Hawkeye dislikes wearing a uniform, treats all patients alike regardless if they are military or civilian, friend or foe, and enjoys playing games and pulling pranks. Burns is strictly by-the-book, refusing to provide medical attention to anyone who isn’t allied military, and is therefore often the butt of Hawkeye’s pranks. This classic “odd couple” character duel fuels much of the film and the show. Houlihan starts out much like Burns, but as the show progresses she becomes more and more open minded and less rigidly bound by army protocol.

Alan Alda in M*A*S*H

The doctors at the M.A.S.H. 4077 treat everyone from soldiers with war wounds to pregnant civilians. They give check-ups on the children at the local orphanage, set broken bones, perform appendectomies, and do everything they can to keep people alive, using humor as a means of dealing with the gruesome realities of the war.

The combination of comedy and medical drama made the show immensely popular. The final episode, “Goodbye, Farewell and Amen” (S11:E16, February 1983) was the most watched U.S. television broadcast until it was surpassed by the Super Bowl in 2010. It remains the most watched series finale of all time with 105.97 million viewers, according to CBS News. The show’s success resulted in the spin-offs Trapper John, M.D. (1979 - 1986), the short-lived AfterMASH (1983 - 1985) and W*A*L*T*E*R (1984), which wasn’t picked up after the pilot episode.

Gary Burghoff as Corporal Walter “Radar” O’Reilly with his teddy bear in M*A*S*H

Since its finale in 1983, countless shows have continued to reference, quote, and parody M*A*S*H, including Futurama (1999 - 2013), Arrested Development, (2003 - 2006, 2013 - ) Grey’s Anatomy, (2005 - ) Archer, (2009 - ) 30 Rock, (2006 - 2013) Friends, (1994 - 2004) The Simpsons, (1989 - ) St. Elsewhere (1982 - 1988), Sesame Street (1969 - ), and That ‘70s Show (1998 - 2006), to name a few. What’s more, M*A*S*H paved the way for future medical comedy-dramas such as Scrubs (2001 - 2010) and Doogie Howser, M.D. (1989 - 1993). The cultural impact and endearing characters of M*A*S*H have caused the show to endure to this day.

Big Bird and his teddy bear, Radar