Prognosis Negative is a fictional movie referenced in the popular Seinfeld television series. In several episodes it was mentioned in the dialogue and in at least one episode a movie poster for it was visible. Such fictional works were a recurring gag in the series, but Prognosis Negative had its roots in an actual screenplay written by Seinfeld co-creator Larry David in the 1980s. It was never produced.
In Season Three’s fourth episode, Elaine wanted to see Prognosis Negative with Jerry, and thus refuses to see it with George when Jerry can't go because of the dog he is watching. Jerry eventually sees it with George; then later he is forced to sit through it again with Elaine.
According to an interview with Terry Gross on NPR, Prognosis Negative “...is about a single guy who is unable to commit to a relationship. He finds out an ex-girlfriend has six months to live and decides it's perfect...he can commit without worrying about the long term consequences.”
Robert Weide, who directed the faux documentary which would become the beginning of Curb Your Enthusiasm, met Larry David through his screenplay for Prognosis Negative.
Also "PROGNOSIS NEGATIVE" is what Judith (Bette Davis) sees on her medical records in the 1939 movie Dark Victory. It's how she knows she has not got long to live.
The term also appeared in “The Junior Mint”. After surgery on Elaine's new love interest Roy, which was watched by Jerry and Kramer (and during which Kramer accidentally caused a junior mint to fall into Roy's open abdominal cavity), Elaine came to Jerry's apartment. Upon entering, she immediately says, "Prognosis negative." She is referring to Roy's condition post-surgery.