'ER' trivia and fun facts

Kellie Martin (Lucy Knight) left the series when it became too painful to work in a medical show following the death of her sister.

Originally planned as a film, which Steven Spielberg was supposed to direct.

The longest running relationship on the show was between Doug and Carol.

Carol Hathaway (Julianna Margulies) was supposed to be brain-dead from a suicide attempt in the first episode, but the character was revived for the series. For the first episode, Margulies was credited as a guest star.

The entire main cast of the first season also appeared in the fifteenth and final season.