The character played by Asia Argento is inspired by her half-sister Anna (Nicolodi's daughter from a previous marriage) who actually suffered from anorexia. Anna died in a scooter accident in 1994 shortly after the film's release, but she is seen in the actual movie during the closing credits dancing in the balcony.
An opening sequence was supposed to feature Tom Savini being accidentally decapitated while the event is witnessed by the killer therefore triggering his/her dormant trauma.
Dario Argento's usual collaborating rock band Goblin were originally suggested to write and perform the music score for the film, but were declined by the American producers who wanted something more friendly to the American audience, therefore Pino Donaggio's orchestral score was used.
Piper Laurie revealed in 1997 that she never even bothered to see the finished film because she heard it was terrible, and that she and Frederic Forrest would constantly sit through the entire shooting laughing.