Nurse Mildred Ratched is the primary antagonist of the book One Flew Over the Cuckoo's Nest and its 1975 film adaptation. She is the strict, steely and cold head nurse at the mental institution that she works and directs.
She was named the fifth greatest villain in movie history by The American Film Institute. Ratched is often considered among the most hated characters in movie history.
She is portrayed in the film by Louise Fletcher, who also portrayed Olivia Foxworth in Flowers in the Attic.