Stephen Sommers deliberately chose to avoid the style of transformations from other werewolf films, where the character would usually grow hair as part of the change. Instead the decision was made to have the character rip his skin off to reveal the werewolf form underneath, going with the idea that the beast "comes from within".
The place where Van Helsing and Anna fight Dracula's three wives is the same place where Frankenstein (1931), Dracula (1931), and The Wolf Man (1941) were filmed. The set is called the Court of Miracles, and it's part of the studio tour at Universal Studios Hollywood.
The film was intended to start a series of "Van Helsing" adventure movies. However, the reviews were bad, and box-office returns were far below expectations. All plans for a sequel were dropped within several days of the film's opening.
Stephen Sommers wanted Kate Beckinsale for the role of Anna, but feared it was too similar in tone to the vampire/werewolf film Underworld (2003) which she was shooting at the time, and he didn't ask her. Eventually her agent got Sommers to send the script, and Beckinsale immediately signed on.
Shuler Hensley, playing Frankenstein's Monster, also stood in as a body double for the CG Mr. Hyde for fight scenes between him and Van Helsing. Shuler wore a cardboard cutout with Mr. Hyde's face on top of his head so Hugh Jackman could have a point of reference when looking at his face.
Stephen Sommers claimed in an interview he changed the main character's name from Abraham Van Helsing to Gabriel Van Helsing, as he did not think he could have a lead character named Abraham. The Irishman who wrote Dracula, Bram Stoker, named the character after himself - Bram being a shortening of Abraham.
At some point in pre-production, a cameo appearance by the Gil-Man from Creature from the Black Lagoon (1954) was slated to appear in the underground cave where Van Helsing and Anna discover Frankenstein's Monster. However, this idea was dropped before filming began. (Stephen Sommers was once rumored to be attached to a remake of "Creature...")
A spin-off television series was pitched to NBC. To have been called "Transylvania", it was to have featured a wild-west Sheriff taken to Europe to battle monsters, with occasional guest appearances by Hugh Jackman as Gabriel Van Helsing. The series idea was stillborn, partly because make-up, effects, and location shooting in Romania would have been too expensive, and partly because the film's opening weekend box-office was far below expectations (which also doomed a proposed sequel to the film).
While the film is an homage to the 1930s and '40s Universal Monster horror films, the inclusion of Mr. Hyde is an oddity, as he was never one of the Universal Monster roster. Instead, the films based on Hyde during that time were made for Universal's rival MGM. However, in 1953, Universal did feature the monster in the comedy Abbott and Costello Meet Dr. Jekyll and Mr. Hyde (1953).
Right before Dracula says" I give you Van Helsing" in front of the other vampires, you can hear trumpets play the first musical phrase from the song "Castle Dracula" from Castlevania: Symphony of the Night.
The film was storyboarded and previsualized with the intent of shooting the film in the anamorphic 2.35:1 format, like Stephen Sommers' previous films. The aspect ratio was changed to 1.85:1 in order to better accommodate Dracula's vertically-oriented castle without having to extend the sets.
So that the production company can hold certain rights to the character, the original character from the Dracula series Abraham Van Helsing was changed to the new "kid brother" Gabriel Van Helsing instead.
The scene of Carl loading up Gabriel with gear to fight the vampires is a tribute to the routine in most James Bond movies where Q arms Bond with all the latest technological gadgets for the next mission. Hugh Jackman was reported to be in the running to play James Bond at the time.
When Carl is flirting with the villager after a vampire attack, the villager's make-up changes. Her face goes from being grimy and plain-looking, to clean and freshly made up, once she learns that monks are not celibate.
Mr. Hyde appears to be modeled after the late French professional wrestler André René Roussimouf, famously known as André the Giant. It is also worth noting that while the story of Dr. Jekyll and Mr. Hyde takes place in London, Van Helsing encounters the character in Paris.
Shuler Hensley reprised his role of Frankenstein's Monster in Mel Brooks's stage adaptation of Young Frankenstein (1974). Co-starring Roger Bart as Dr. Frederick Frankenstein, the play opened at the Hilton Theater, New York City on November 8, 2007. It closed on January 4, 2009 after 29 previews and 485 performances.
When Anna is about to kill one of Dracula's wives, the wife makes a short speech about how she is going to kill her, thus giving Anna time to get the silver stake from Carl and stab her. As she does, she says, "When you want to kill, kill. Don't talk". This is very similar to Eli Wallach's line in The Good, The Bad, and the Ugly when he is in a bathtub listening to a cowboy who making a speech before trying to kill Wallach. Wallach says, "When you want to shoot, shoot. Don't talk".
The last scene shot for actor Will Kemp was actually his death scene. It was filmed in Griffith Park in Los Angeles, California. In the scene, he is to lay against a rock. What the crew did not know, was that there were a lot of spiders in the area, and when Kemp's scene was finally completed, he went home with numerous spider bites on his back and arms.
Throughout the movie, it is implied that Van Helsing is the archangel Gabriel. He mentions "fighting the Romans at Masada" (to which Carl responds, "That was in 73 A.D.!"), referring to the Siege of Masada in the First Jewish-Roman War. Later, Dracula gives his first name as "Gabriel" and refers to him as the "Left Hand of God". Gabriel is considered God's messenger, and was the angel to tell Zechariah and the Virgin Mary of John the Baptist and Jesus' births respectively.
One of the last shots, in which Van Helsing transforms back into a human from a werewolf, was originally to be a nude scene (for Hugh Jackman), however, Stephen Sommers felt that it would have been too distracting to the viewer, and disrupt the emotion of Anna's death from the scene. The nude shot is still used in the film, however, a CGI loin cloth was animated to cover Jackman's rear.
Towards the end of the movie, during the battle between Dracula and Van Helsing as a werewolf, Van Helsing bares the claws on his right "hand" in a manner very similar to the way the X-Men's Wolverine, also played by Hugh Jackman, bares his.
The effect of the vampire brides' flying forms was pulled off by having the face and hair of the actresses made up as it would appear in the film and having them wear motion capture suits and film them against green screen. The appearance of the three brides is based on the brides in Bram Stoker's Dracula (1992). Ironically, Silvia Colloca played the queen bride as Monica Bellucci did and the two have been compared often. Also, the fair haired vampire (Marishka) dies first in both movies.