The Swedish film censors required numerous cuts in the film, before authorizing its release. Among the censored scenes were the closeup of the finger being removed from the hanged man's hand, the trampling of the cross in the witch's sabbath scene, the shot of the oozing infant held over a cooking pot, a closeup of a woman's face while she is on a torture rack, closeups of several instruments of torture being employed, and a shot of a demon embracing a nude woman (all these shots have since been restored to the film).
Maria, the weaver (one of the persecuted witches), was played by Maren Pedersen, who director Benjamin Christensen allegedly discovered while she was selling flowers on a street corner. Pedersen claimed that she was the first Red Cross nurse in Denmark. During the shoot, she reportedly turned to Christensen and said, "The Devil is real. I have seen him sitting at my bedside." Christensen was so struck by this confession of modern demonic activity (or at least the belief in modern demonic activity) that he incorporated this anecdote into the film itself.
Even though most scenes were filmed in interior studios, because Benjamin Christensen felt that the actors' performances would be best influenced by a more dark and ominous atmosphere, most of the film was shot at night, almost unheard-of at the time.
Director Benjamin Christensen originally planned to write the script with the help of historical experts, but that plan fell through after he discovered that most of the experts he had in mind were against the making of the film.
Due to the type of emulsion of the film stock used, the blue in many of the actors' blue eyes did not register, giving their eyes a glazed, unnatural appearance.