When Stella enters a trance and speaks in Spanish during the seance, she says, "Listen, listen! It's not her! It's not her! Do not believe anything! Do not listen to her, because she's lying! You thief! Thief of my love!"
Moyna MacGill (the mother of Angela Lansbury) has an uncredited role as the customer who enters the cigar shop while Roderick is speaking with the proprietor.
Paramount added special effects to the film, having decided at the last moment to emphasize its supernatural premise. The effects were removed by censors when the film was distributed in England.
Paramount contract player Elizabeth Russell posed for the painting of Mary Meredith. She and actress Lynda Grey, who played the ghost, closely resembled each other. At the time the painting was created, Grey wasn't available to pose.
There is a line of dialogue near the end of the film in which Rick assures Lizzie, "We will do nothing tonight that the priest wouldn't approve of." He is referring to Father Anson, who had a major sub-plot in the novel (he wanted to perform an exorcism on the house) but whose character and sub-plot were deleted entirely from the filmed version. This one odd line, lifted almost verbatim from the novel, somehow made it into the final cut.