Continuity mistake: In the scene where Benicio Del Toro is in the tavern listening to the townsfolk discuss his brother's death, you see him finish his alcoholic beverage, however, in the next shot his glass jumps to being half full.
Other mistake: When Lawrence is looking at his wound in the mirror, it has slightly healed. Later, when Sir John visits Lawrence in the asylum, he shows the bite mark he got from the feral child to Lawrence. Since Sir John is also a werewolf, the bite mark should not be there.
Gwen Conliffe: It is said, there is no sin in killing a beast, only in killing a man. But where does one begin and the other end?
Trivia: Makeup artist Rick Baker has a cameo appearance in this film. He's the man who whistles to his comrades who are approaching the gypsy camp then a few seconds later, gets killed by the werewolf.