MASH's only female main cast member, Margaret Houlihan is also known as "Hot Lips" — a nickname that haunted her for quite a long time.

Summary

• Margaret Houlihan's nickname "Hot Lips" in MASH was given to her in the movie when she accidentally referred to her own lips as hot during an intimate moment with Frank Burns.
• The nickname is carried over to the TV show, but eventually dropped as the character of Margaret develops and becomes more nuanced.
• Over the course of 11 seasons, Loretta Swit's portrayal of Margaret allowed her to outgrow the nickname and become a fully developed character.

There's an interesting and humorous reason why Loretta Swit's Margaret Houlihan is called "Hot Lips" in MASH. The MASH franchise is known for its many nicknames. Alan Alda's Captain Benjamin "Hawkeye" Pierce is called Hawkeye because of his father's penchant for The Last of the Mohicans, while Walter O'Reilly is dubbed Radar because he can hear the choppers coming before they even get near the unit. However, there's still confusion as to why Margaret has been given the moniker "Hot Lips."

As the only main female character in MASH, Margaret goes through an extensive personal arc in the series. She starts with an illicit affair with Frank Burns and then breaks up with him after several years. Margaret then quickly gets engaged and marries Donald Penobscott, which also ends in a contentious divorce. Despite her stormy love life, one would be hard-pressed to find fault in her commitment to her sworn responsibility as a military nurse. Unfortunately, being called "Hot Lips" doesn't quite capture that particular quality of hers.

Margaret Accidentally Gave Herself The Nickname "Hot Lips" In MASH's Movie

Like the majority of MASH TV show characters, Margaret makes her first live-action debut via the 1970 MASH film and is played by Sally Kellerman. It is also in the Robert Altman project that explains why she is called "Hot Lips." In the movie, Margaret accidentally gives herself the moniker while she and Frank are having some alone time in her tent. Apparently, it is bugged by the public address microphone as part of Trapper John McIntyre and Tom Skerritt's Duke Forrest, among others, so they can hear them. In the heat of the moment, Margaret says "Ohh, Frank my lips are hot.. Kiss my hot lips!"

Since then, Kellerman's Margaret has been dubbed "Hot Lips" as a way for Trapper, Duke, and the rest of the mischievous members of the outfit to poke fun at her. The moniker is carried over into the MASH TV show on CBS. Similar to the movie, the sitcom starts with Margaret in a relationship with Frank, and they consistently spend time together around the facility. However, despite being a longer form of storytelling, the show doesn't actually cover the particular moment in the feature where Margaret calls herself "Hot Lips."

Why The MASH TV Show Stopped Calling Margaret Hot Lips

While the film sticks with the nickname "Hot Lips" for Margaret, the moniker is eventually dropped in the MASH TV series. Ultimately, Swit's character is only exclusively called by her given name. This is because of the character's development in the series. Because Altman's movie has a limited runtime, it isn't able to fully flesh out the character the way that the CBS comedy does. Having stayed with the character for 11 seasons, Swit understandably got invested in her story and asked the writers to add more nuance to her. By the time MASH ended, Margaret was already a fully developed character, fully outgrowing her nickname.