Common Sense Note
Parents need to know that Byzantium is artier and moodier than most vampire movies. It's not particularly for either the I Am Legend crowd or Twilight lovers, but fans of Let the Right One In may enjoy it. Vampire violence is strong, with great gushes of blood, killings, and dead bodies; two characters are beheaded. Several minor characters are prostitutes, and a major character used to be one as well. There's no nudity, but there are many sexual situations and plenty of innuendo and revealing outfits. Byzantium suggests that the prostitutes are addicted to drugs, though it does this solely through body language; no drugs are shown or mentioned. Language is sparse but does include a few uses of "f--k," "s--t," and more.
Several of the supporting characters are prostitutes, and the main character is shown to have been one previously. No nudity, but characters wear revealing clothing throughout, such as lingerie and fishnets. Partly naked bottoms and lots of cleavage are on display. Sex acts -- a lap dance, oral sex, etc. -- are begun and/or suggested but not fully shown. Some strong sexual innuendo.
Lots of bloody vampire violence. Here, vampires slice their victims not with fangs, but with a sharp fingernail that grows when needed. There's a great deal of blood, lots of killing, and several dead bodies (including charred and rotted corpses). Two characters are beheaded with a wire. One character -- who takes an anti-coagulant -- gets a cut on his wrist and bleeds profusely. There are also some intense moments of fighting and punching, as well as arguing. In one sequence, several waterfalls turn blood-red (though it looks more like colored water than blood).
Language isn't constant but does include a few uses of strong words including "f--k," "c--t," "s--t," "c--k," and "bitch."
The movie is about telling the truth to lead a more fulfilling life, even though lies are more protective. In a subplot, the movie celebrates fighting for what you believe is right, rather than following long-established rules that may be wrong. On the downside, "wrongdoers" are often killed.
Drugs / Tobacco /
It's suggested that some of the supporting prostitute characters are "high" or on drugs, though they're never shown taking anything, and nothing is ever mentioned out loud. They just act sleepy and dopey.