This is a version of the Marquis de Sade's story, The 120 Days of Sodom, a story about four powerful men who enslave two dozen teenagers and torture them repeatedly. Unlike the book the film is set in the Salò Republic, the Nazi puppet state in northern Italy, in the year 1944. Pier Paolo Pasolini directs his final film. The four powerful men in the story are referred to as the Duke, the Magistrate, the President and the Bishop. To kick things off they marry each other's daughters and then begin to have young males and females kidnapped (18 in all, 9 of each gender). They also have four older prostitutes join in and this whole multitude marches over to some palace. Mind you, the time period means that the Nazi occupied Salò Republic is on its last legs and on the cusp of being crippled by the Allied forces. So the setting gives us sort of an end of days feeling right from the get-go. The content and commentary certainly continue with that subject matter throughout.
The film is set up in four stages, the first being the ante-inferno, which refers to those who are not quite condemned to hell but also not allowed into heaven either. The film's setting is meant to feel like a brief moment in purgatory with its isolated party of characters doing unspeakable things before judgment, and then it all must end. The second stage is the circle of manias, or obsession, where we see the sexual humiliation of the film manifest itself further. The third stage is the circle of excrement, which is where we see the characters consume feces. Pasolini has used this as a metaphor broadly for the perverse level of consumption depicted in the film overall, and directly as a commentary on mass-produced foods and consumerism. The fourth stage is the circle of blood, this is where those who do not partake in this bizarre corruption are brutally murdered in various ways. The stages bring us further and further downward into degeneracy, which Pasolini has applied strongly as a denunciation against capitalism and fascism.
If you found any interest in the above commentary, then I assume Salò may be just the film for you, but I assure you that the film is definitely not for everyone. It is up front with its content. It's controversial for many different reasons, but primarily it is the visual content that turns people away. Yes, it's not as violent as Saw and the nudity is not quite as pretty as it is in some movies, but Salò is anything other than an exploitation film. One may even argue that it is the exact opposite of exploitation. Perhaps it is Salò's censure of exploitation that makes it truly disturbing as a modern social commentary.