Trivia: While Josh is being tortured by the guy with the shaky hands (right when he's slicing the back of Josh's ankles), he is screaming and wiggling in the chair. As he was doing this, the leg of the chair really crushed one of Derek Richardson's (Josh) toes. Despite the pain, he continued to act out the scene without telling anybody because he thought it would be more realistic.
Trivia: When Paxton is about to be tortured, he begs to the man in German. Director Eli Roth decided not to add subtitles, preferring to leave what was said a mystery. The lines translate as "If you kill me, it'll destroy your life. Every time you close your eyes, you'll see me. I'll be in your nightmares every night, your whole life. I will ruin it."
Trivia: The Asian businessman who Paxton encounters outside of the torture-center (who warns Paxton that he could spend "all his money" inside) is played by controversial Japanese filmmaker Takashi Miike in a cameo. Both director Eli Roth and executive producer Quentin Tarantino are huge fans of his films.
Trivia: The original ending of the film was vastly different than the theatrical ending. In the original ending, rather than killing the "Dutch Businessman" at the train station, Paxton would instead locate and kidnap his young daughter from the station, leaving the businessman screaming hysterically on the platform, unable to find her. Director Eli Roth considered this to be a far worse form of vengeance than killing him, as he made it clear early on that his daughter was the most important part of his life. However, test audiences who saw the ending felt it was too dark and bleak, and so the theatrical ending was added in re-shoots. The original ending was finally included in some DVD releases of the film.