Lucio Fulci was arrested on child endangerment grounds due to the infamous scene where a fully nude Patrizia (Barbara Bouchet) flirts with the underage Michele (Marcello Tamborra). The charges were dropped when Fulci explained that the actors' close-ups were filmed separately, and that the shot of Michele walking towards Patrizia with a pitcher and glass of orange juice was achieved by having an adult dwarf actor, Domenico Semeraro, stand in for Tamborra (if you look carefully, you will notice how different Semeraro's facial structure is from Tamborra's).
Lucio Fulci has said in numerous interviews that he ranks this movie as his most personal favorite of all the movies he directed in his career.
Composer Riz Ortolani reused a small segment of music from this film in his later composition for Cannibal Holocaust (1980).
None of the main cast are actually Italian: Florinda Bolkan is Brazilian, Tomas Milian is Cuban-American, Barbara Bouchet is German-American, Irene Papas is Greek; and Marc Porel & Georges Wilson are both French.