Author Kesey stated that he based Ratched on the head nurse of the psychiatric ward where he worked. He later ran into her at an aquarium, realizing "She was much smaller than I remembered, and a whole lot more human." The 1940s hairstyle was, according to Louise Fletcher, "a symbol that life had stopped for her a long time ago". In Ken Kesey's novel, Nurse Ratched is described by Chief Bromden as having a face that is smooth, calculated and precision-made like an expensive babydoll, skin like flesh-colored enamel that is a blend of white and cream with baby-blue eyes, she also has a small nose with pink little nostrils. But the only things on Ratched that doesn’t match her perfect appearance is her having lips and fingernails that are both the color of orange, as well as carrying oversized breasts, completed with a heavily starched white nurse uniform that tightly conceals her top-heaviness to hide her femininity. In Miloš Forman's film adaptation, Nurse Ratched is shown with pink lips and pink fingernails, skin that almost matches the color of her lips and fingernails, has gray-blue eyes, she still has a small nose with pink little nostrils, she still has a face like an expensive doll, she has a 34B bust size, she still wears a perfectly clean uniform that indicates her obsession with cleanliness and order, she also wears her uniform loose this time because she has no breasts that are massively endowed to cover up, she wears a 1940s hairstyle that resembles devil horns, and she is given the full name "Mildred Ratched".
Nurse Ratched is the head administrative nurse at the SalemState Hospital, a mental institution where she exercises near-absolute power over the patients' access to medications, privileges, and basic necessities such as food and toiletries. She capriciously revokes these privileges whenever a patient displeases her. Her superiors turn a blind eye because she maintains order, keeping the patients from acting out, either through antipsychotic and anticonvulsant drugs or her own brand of psychotherapy, which consists mostly of humiliating patients into doing her bidding. Her tyrannical rule and her hurtful personality stems from her time as an army nurse during World War II. When Randle McMurphy arrives at the hospital, however, he flouts her rules with impunity, and inspires other patients to follow. Her attempts to cow him into submission—at first with threats and mild punishments, then with shock therapy—are unsuccessful, serving only to fuel his defiance. McMurphy helps organize an unauthorized party late one evening, and they invite two prostitute friends, Sandra and Candy, into the asylum. After noticing fellow patient Billy Bibbitt has a crush on candy, McMurphy encourages her to relieve him of his virginity. Suddenly, Nurse Ratched catches Billy and Candy in the act. Furious, she threatens to tell his mother. Billy begs her not to tell, and blames McMurphy and the other patients for orchestrating the event. Nurse Ratched then sends him to wait in the ward doctor's office as the authorities are called. When Dr. Spivey finally arrives, he finds Billy dead, having committed suicide by cutting his throat. Nurse Ratched blames McMurphy for his death, and in a fit of rage, McMurphy breaks into the Nurse Station and attacks her, nearly strangling her to death before he is pried off.
Despite having McMurphy lobotomized in retribution, the attack has left Nurse Ratched weakened and bruised, and she is unable to control the ward any longer as the patients are no longer afraid of her.
Nurse Ratched was a recurring character in the ABC series Once Upon a Time. She is portrayed by Ingrid Torrance and works for the Evil Queen as a nurse in the Storybrooke Sanitarium. Although she appears in several episodes starting in the first season, her name is revealed in the fifth season premiere "The Dark Swan". Sarah Paulson will portray a younger version of the character in Ryan Murphy's upcoming Netflix adaptation, Ratched, a prequel to One Flew Over the Cuckoo’s Nest.