Michelle Rodriguez had informed her agent that if anyone ever wrote a script about Resident Evil that she wanted to be a part of it. Her agent duly put her in contact with Paul W.S. Anderson when his screenplay was bought.

This film was originally titled 'Resident Evil: Ground Zero', but the title was changed to just 'Resident Evil' after the September 11, 2001 terrorist attacks on the USA, where the remains of the World Trade Center is referred to as ground zero.

Milla Jovovich did all of her own stunts except the pipe jump in the sewer scene. A stunt double was used because her agent thought she would get strangled by the hanging wires.

During the shooting of the sewer scenes, Milla Jovovich accidentally right-hooked Paul W.S. Anderson in the face, giving him a big black eye. By the end she accidentally hurt about three cast and crew members.

Anna Bolt, who plays the drowned research scientist, is the sister of the film's producer Jeremy Bolt.

The makeup department and crew had a hard time dealing with the dogs, who kept licking the zombie makeup, blood and meat off of themselves.

Milla Jovovich said the real reason she did this movie was because her brother Marko was a huge fan of the video games.

One of the most popular scenes in the film - when Alice runs up a wall and flings round to kick a zombie dog in the head - took 3 months of training for Milla Jovovich.

The presidents of Capcom Japan and America have cameos as zombies. Capcom created the Resident Evil series.

According to Milla Jovovich on the Blu-ray and DVD commentary, it was a crew member's birthday on the last day of filming. Bottles of champagnes were brought on the set. Paul W.S. Anderson was worried that the cast and crew would drink too much, but they said they'll just have a glass and no more. Sure enough, the whole cast and crew got drunk whilst waiting for filming the final scene in the film.

Milla Jovovich and Paul W.S. Anderson, who met on the set of "Resident Evil", got married on 22nd August 2009.

Sony Pictures, had hoped at one time to make the film PG-13 so as to make the film more marketable to the younger video game fans, but director Paul W.S. Anderson insisted that to be true to the game, the film must be rated R.

The pass code for opening the door in dining hall B, the one Kaplan has trouble remembering, is 04031965. Writer and Director Paul W.S. Anderson was born on 04 March 1965.

There is a shot of Alice's eye close up near the end of the film. This is a direct reference to the first game in the series; Resident Evil (1996). The close-up eye shot is the logo title screen of the game.

Milla Jovovich had signed on to the movie with Alice being the main protagonist and the center of most of the action. When Michelle Rodriguez came on board, the script was re-written to give most of the cool action scenes to her character Rain, and Alice turned into more of a damsel in distress who often had to be rescued by the supporting characters. When Jovovich read the re-writes, she convinced writer/director Paul W.S. Anderson to rewrite her character as more action-oriented.

Though the film is set in America, filming took place in Germany. Much of the movie was filmed in unfinished stations of Berlin underground, such as the train scenes.

In December 2001, Sony gave fans a chance to design the film's poster with the prize being an undisclosed amount of cash, a free screening of the film and the chosen design being used on all the advertising material. Nick des Barres, a 23 year old aspiring actor and ex-video game magazine designer, won the competition.

The zombie guard who attacks Alice after the appearance of the first dog zombie is the film's stunt coordinator and trainer, Jaymes Butler.

The main actors were told to prepare for the film by getting copies of the games and playing them through. Some of them didn't know if they could complete them in time so they had to get video copies of other people beating the games and then watch it.

Originally set to star Sarah Michelle Gellar as Alice. Jennifer Love Hewitt, Kirsten Dunst and Natasha Henstridge were some of the actresses considered to play Jill Valentine when different scripts were being developed for the film.

Professional dancers were cast as the more action-oriented zombies. They had to actually be flexible enough to do the stunts required to perform the disturbing movements.

Before the team enter the hive they set a timer of 3 hours to get out. In the video game in order to unlock most bonuses you have to beat the game in 3 hours or less.

Like in the games, after something is switched on/off, something else happens elsewhere. When the Red Queen is deactivated for the first time, all doors elsewhere are opened.

To prepare for their roles, the actors playing commandos and Milla Jovovich and Eric Mabius had a week of commando training (climbing, martial arts, weapons handling, etc.) with former Navy SEAL Jaymes Butler.

George A. Romero, director of Night of the Living Dead (1968), was originally attached to write and direct, but left the project in 1999 due to creative differences over the script. The project was dormant for over a year before Paul W.S. Anderson signed on to write and direct. Anderson later claimed that he had once locked himself inside his apartment for 4 weeks while playing the first three Resident Evil games back-to-back, and became so obsessed with them that he contacted his producer Jeremy Bolt, telling him that they had to make this series into a movie.

Jason Isaacs - a personal friend of director Paul W.S. Anderson - took a day off from filming The Tuxedo (2002) for his voice cameo narration.

The original cut of the movie got the dreaded NC-17 rating due to graphic violence and nudity, so all of those scenes had to be cut down to obtain the more commercial R rating. After the movie came out, director Paul W.S. Anderson said in interviews that he would release his director's cut with all the scenes that were cut for rating, and some that were cut for other reasons, such as pacing issues, but this never happened. There was however a VHS workprint of the film available in early 2000's with the alternate title 'Resident Evil: Genesis', which was also used during test screenings of the film and was fully uncut, but it has never showed up anywhere again since then.

In the movie, Alice's fake husband is named Spence. This is a reference to Oswell Spencer, one of the three founders of Umbrella Corporation in the game series. The first game took place in his huge mansion, the Spencer Estate, which also hides a secret underground lab where the T-Virus was developed.

The second movie based on a video game directed by Paul W.S. Anderson. The first was Mortal Kombat (1995).

The bruises and scratches seen on Alice's (Milla Jovovich) body were originally done by make-up, but as the film goes on, she got more and more real bruises. The make-up department actually had to start covering up the real bruises rather than creating fake ones.

One of the smaller headlines on the newspaper at the end of the film references the S.T.A.R.S. from the first Resident Evil video game.

George A. Romero's unproduced script features the game character Jill Valentine as the female lead. The character would debut in the next film, Resident Evil: Apocalypse (2004), instead.

To help him achieve the underground look of the film, set designer Richard Bridgland visited nuclear bunkers in the UK and in Europe.

Director Paul W.S. Anderson hired composers Marco Beltrami and Marilyn Manson because he wanted an edgy score, similar to those that appeared in John Carpenter's early films.

Even though they're everywhere, the word "zombie" is never spoken in this film.

When this film debuted, it had the largest opening weekend for a European-financed film.

San Francisco is the cityscape shown outside the fake windows, near the elevators in the Hive.  You can tell, because there's a view of the Trans America building, which is in San Francisco.

Even though Colin Salmon's character is referred to- and credited only as One, his real name is James Shade.

The underground tram has a serial number on the front of the lead car that reads "ALEXI-5000". Alexia Ashford is the final antagonist of Resident Evil - Code: Veronica (2000), and underground cable cars are a recurring mode of transportation in the Resident Evil games

The banner on the bus in the end of the movie shows several toys on the right, among them a teddy bear. The text on the left reads: "At Umbrella Medical, we try to make teddy a little softer". Along the bottom, it reads: "Umbrella Medical - Sheltering Your Family."

Matt stating that he is a cop who recently transferred in could be a possible reference to Leon Kennedy in Resident Evil 2 (1998), who is also a cop who just transferred to the Raccoon City police department at the beginning of the game, to find that the city has been taken over by zombies.

The Licker's nickname on set was Clint.

Producer Jeremy Bolt shaved his hair to play one of the zombies.

The crows that Alice sees at the beginning of the film are digitized.

Among the many references to Alice in Wonderland, a major one is the first onscreen kill by the Red Queen, Dr. Black tries to climb out of the elevator, and is eventually beheaded. The Red Queen from the original story is notorious for her obsession with beheadings, as illustrated by her frequent line "Off with her head!"

Red hair dye was used to create blood on Rain's head near the end of the film.

Michaela Dicker, who plays the Red Queen, previously collaborated with Paul W.S. Anderson on The Sight (2000), a made-for-television horror film. This would be her last acting role, not wishing to pursue a full-time film acting career. The Red Queen was therefore re-cast for Resident Evil: Retribution (2012), and would be played by Anderson's and Milla Jovovich's daughter Ever Anderson in Resident Evil: The Final Chapter (2016).

Shot on some of the same German sets as Enemy at the Gates (2001).

Reference to Resident Evil Survivor (2000): Someone loses their memory and at the end it is returned. In the game, protagonist Ark Thompson lost his memory due to a helicopter crash and regains it at the end after battling a Hunter that tried to kill Lott Klein; in the movie, Alice lost her memory up until the end of the next movie Resident Evil Apocalypse because of a nerve gas that was leaked into the mansion from the shower drain.

The film is included on the film critic Roger Ebert's "Most Hated" list.

Rain uses a Springfield Armory Mil-Spec M1911A1 with Pachmayr grips and an accessory rail as her sidearm. This weapon is also shared between the characters, specifically Alice, when all of their other weapons run out of ammunition.

In the commentary it's mentioned that actor James Purefoy who played Spence used his own blue jeans instead of the costume prop.

In the first draft of the script Kaplan was simply referred to as "Twelve". His full name was Isiab Tagawa Mercurio.

The final fate of the Matt character is known to fans of the games and to those who watched the sequel.

The Umbrella Corporation symbol looks remarkably like the symbol for the 8th Army, even the colors are the same, just rotated a little.

All the visual effects were done by the Computer Film Company, an FX house based in London.

After returning to the laser hallway where the Military Commandos were sliced by lasers, the survivors find that the bodies have vanished. This is a direct reference to the earlier Resident Evil games, in which dead bodies would vanish if you leave and reenter an area.

The Red Queen mentions that hair and fingernails continue to grow after death, which is actually a common misconception. All growth stops upon death, but due to the body losing water from dehydration, the skin dries out and shrinks. It starts pulling away from the hair follicles and nail beds, creating the illusion that they become longer.

Among the many connections to Alice's Adventures in Wonderland: The main character's name is Alice. The central computer is named 'Red Queen'. The Red Queen needs to kill someone to prevent them from spreading the virus (the Umbrella employee in the elevator), so she makes the elevator chop off their head ("Off with her head!"). A white rabbit was used to test the T-virus, and kept in The Hive, an underground lab ('Down the rabbit hole'). Alice kills zombie Lisa with an Alice in Wonderland paperweight. To enter the Hive they go through a mirrored door (Through the Looking Glass). The Red Queen succeeds in cutting off another head: the medic in the laser hallway. Kaplan worries about time, as does the White Rabbit. Matt is sitting on the ledge when Rain and JD hear the first zombie; this is mentioned in the commentary as a reference to the Caterpillar.

The password into the Red Queen's Chamber is: 12177.

None of the main characters from the Resident Evil video games appear.

Although she never had any problems with nudity in her films, Milla Jovovich did ask for the originally scripted ending to be changed and cut down on the amount of time she was supposed to be nude in the scene. Originally, in the script, Alice wakes up in the hospital fully nude, and spends more time walking around the hallways and rooms before walking out on the street while she's still naked. Jovovich didn't want to film the part where she's walking nude outside on the streets, which led to scene changes including Alice wearing something to cover her up.

88 characters died during the zombie outbreak in the lab.

Although the movie was only loosely inspired by the Resident Evil games released at the time, it ended up as inspiration for some of the later games. The laser corridor sequence was later referenced in both Resident Evil 4 (2005) and Resident Evil: The Umbrella Chronicles (2007). The former game saw the return of Ada Wong from Resident Evil 2 (1998) who now shared several of Alice's hallmarks (flowing red dress, athletic skills), while Umbrella Chronicles also featured the Red Queen A.I. and an attack on a high-speed train wagon inside an Umbrella complex.  Lastly, the title font for the movie is the same used in Resident Evil Outbreak and File #2.

When Matt and Alice return to the mansion at the end of the movie the case Alice is carrying is just a box covered in foil. The actual case was locked inside a studio.

A newspaper in Racoon City reads "The Dead Walk!" This is a direct reference to Day of the Dead (1985), in which a newspaper at the beginning of the film reads the same.

In the final scene, when Alice wakes up in the medical facility barely covered by a short garment open at the sides, Milla Jovovich revealing her pubic hair when she gets off the table was an accident. But they kept the shot.

When Matt's arm begins to mutate there are no digital effects until the very end.

In addition to playing the role of the narrator, Jason Isaacs has an uncredited cameo as Dr. William Birkin in the film's ending, who is a character from the games. He was supposed to be expanded upon in potential sequels and have his backstory explored, but Jason Isaacs was unavailable for production of Resident Evil: Apocalypse (2004) so the character was written out of the film. Iain Glen's character of Dr. Isaacs was created as a replacement for him, even bearing Isaacs' name as a tribute (Jason Isaacs and writer/director Paul W.S. Anderson are real-life friends).

Another Alice Through the Looking Glass reference is the fact that when Alice wakes up in the bathroom she is lying next to a chess formed floor. This implies that Alice is right before the beginning of her journey in the Looking Glass land (like a pawn at the beginning of a chess game). In the final scenes Alice and Matt are on the hallway of the mansion's entrance, which has the same chess formed floor with black and white squares. This means that their journey has ended.

Film critic Roger Ebert famously wrote about the Licker: "The vast Umbrella Corporation can turn a little DNA into a monster with a 9-foot tongue. Reminds me of the young man from Kent. Eventually its tongue is nailed to the floor of a train car and it is dragged behind it on the third rail. I hate it when that happens."

The producer, Jeremy Bolt, appears as a zombie several times throughout the movie.

Reference to Resident Evil - Code: Veronica (2000): Matt runs into his sister who is now a zombie and has to watch her "die". This is similar to Steve Burnside having to watch his zombie father die, but by his own hands. Matt's sister is called Lisa, which may be a reference to Lisa Trevor, a character added to Resident Evil (2002), a remake of the first game.

Jason Isaacs, is the narrator at the opening of the film and the voice of the scientist who wants to re-open the hive.

Mistakes

Matt is supposed to be in handcuffs for at least the first 40 minutes of the movie, between one shot it shows him walking swinging his arms without cuffs on.

No one's handwriting matches that on the note, not even the handwriting of the note's original author.

When the second elevator falls in the hive it is shown going from floor 10 to 7 to 9.

Throughout the Laser Corridor sequence, the bodies of the dead teammates continue to disappear and reappear between shots; this is most notable when we are shown from One's point-of-view the laser traveling towards him and multiplying into diamonds to stop anyone from jumping through or dodging it. The bodies are absent from the floor in the long shot showing the laser traveling towards One and only reappear when we are shown One from behind, after the laser has passed through him and effectively killed him.

At the beginning of the movie, Spence is wearing a leather jacket, which he gives to Alice. As the movie progresses, the jacket does not look big on Alice and even looks like a ladies' size.

In the Red Queen's Chamber when the laser first appears, The Medic can clearly be seen looking towards the beam. Yet when it cut backs to her her head is facing the opposite direction.

In the first shot after entering the utility tunnels, the bandage on Rain's bitten hand is clearly missing. In the next shot, it's back on again.

When she enters the Hive, Alice, straight from her shower, wears no makeup. As she travels through the hive, however, her makeup changes from scene to scene. This is especially obvious when her lipstick shade changes drastically several times.

When Alice and Spence are arguing in the lab, her hair changes positions each time the camera returns to her.

The coffee stain on the Mr. Grey's shirt in the elevators, changes from the time he spills the coffee and the time he gets in the elevator, quite noticeably.

Near the end of the movie, when Alice is talking to Rain on the train, in the background, you can see Matt go from moving around to standing still with his hands on the sides of the doorway between shots.

When a television monitor is seen it has a bar code under the screen but when it's seen again the bar code has gone and there's now a logo for a South Korean technology firm.

When Lisa appears, Matt is shuffling through some papers. In one shot he puts down a paper with a graph on it. The very next shot he's again holding that same paper with the graph on it.

When Rain, J.D., and Matt are waiting for the team to get back, Rain hears a noise. As she goes to investigate, we can see Matt's legs jump from spread open, to crossing his ankles in between shots.

When the lasers turn diamond shape they cover the entire area from top to bottom, yet, the rest of the bodies are still whole. Even the bodies on the floor would've been diced. If not then the man with the severed fingers would've still been alive.

Alice's hair changes position from behind her ear to in front of it when she and Spence talk about their memory loss, and he gives his jacket to her.

Alice writes a few words on a notepad in order to see if the handwriting matches the pre-existing message on it. She uses here left hand. However, every time she uses one gun, she favors her right hand.

The lab technician holding the axe is in a water-filled room. After he becomes a zombie, and is walking towards the soldiers, he is completely dry.

When Matt kneels down to examine the blood of the undead Hive worker, he claims that blood only coagulates when you're dead. In truth, coagulation is simply the process of blood clotting around a damaged vessel wall, which indeed happens in living beings. On the contrary, in death, blood doesn't coagulate, but separates, causing livor mortis.

When "One" is being killed by the laser grid he should have fallen into cube pieces but in a later shot when the rest of the team enters the area you only see the bodies of the soldiers but no scattered pieces of "One".

Spence was able to smash the vial of T-Virus and start the outbreak by simply tossing it on the floor like it was made of thin glass. If this vial was supposed to contain the world's most dangerous virus, it would be made of thick, reinforced glass in real life.

At the beginning of the movie, where the vial containing the virus is dropped, the fumes escape into the building through an air duct. This is not plausible, as any clean room that requires people to work in safety suits would be sealed, and therefore not have air vents.

In the Red Queen chamber, One's character is clearly only a few feet from the door. As the laser returns to kill him, you can see through his first person view that there are no bodies and no equipment in the corridor.

When Spence listens in on Alice's conversation, he is using a standard shotgun microphone on a zeppelin shock mount. This is a location sound piece of equipment for film work. Although a shotgun mic does have a decent reach, it is not a suitable telescopic microphone for spy work.

The first and last victim of the slicing laser would have immediately fallen to the floor as the laser passed through their spinal cords, as the muscles required to stand would immediately cease to function with no nerve impulses going to them.

Dr. Blue puts his coffee cup on the table when walking into the lab, right next to a dissected specimen, something a real scientist would never do to avoid cross-contamination.

The severe injuries caused by the laser beams are bloodless.  The cuts would cause a mess of spurting blood.

A group of people are trapped in an elevator and they listen to another elevator dropping. As it falls, we can clearly see the counterweight rising, but when the elevator hits the ground and the wires snap, they just hang there. In a real life situation, the counterweight would've gone slamming towards the ground, pulling the wires along with it.

When the lab at the beginning of the movie is filling with water, the camera scans the female scientist and her name shows up as Dr. Anna Bolt. Anna Bolt is the actress' name while her character is Dr. Green.

Projection of Hive shows lower elevation count after "dining hall" than before, which doesn't make sense if it increased as they went down and that area is lower than the "dining hall".

At the beginning of the movie, you can see the floor outside the elevator bending under the woman's weight as she tries to escape the elevator.

At the beginning of the film, when the virus vials are being loaded to the metal briefcase, the operator of the robotic arm drops a vial, and reaches for another one when its out of the camera's view , but it can be seen in the reflection in the window.

After Alice smashes the undead Lisa over the head with the paperweight, she is shown lying on the floor. The collar of her dress shirt is open and the makeup used to make her appear undead has stained the fabric.

The zombie in the kennel, after being kicked back, as well as before that, can be seen breathing.  Zombies are dead, and the dead don't breath.

When the tactical team first enters the house above the Hive, they are all wearing gas masks, however, none of them has filters attached and would, therefore, be useless.

After Matt is saved by Alice, one zombie falls after soldier stops shooting.

When Rain, Alice, and Matt are watching Spence's death on the monitor, you hear Matt say "What the fuck is that?" but his mouth isn't moving.

When they are first entering the hive and the captain is speaking to Alice, a sound microphone is clearly visible at the top of the screen.

As the swat team makes its way through the flooded labs they stop and in a group shot Spence can be seen mouthing the words "What happened here?" but there is no sound. In the next shot he says it again this time with audio.

When Alice runs along the kennel wall to leap up and kick the last dog, you can clearly see a black wiring harness used for the stunt, under her jacket and dress.

When Alice tries to retrieve the anti-virus box on the train platform, there is an observation camera shot from above with filming equipment visible at the bottom of the screen.

When Kaplan says, "accessing schematics of the hive", it can clearly be seen for a split second that his mouth isn't moving to the dialogue.