While it may seem tame by today's standards; at the time, no one had ever seen anything like it before. The R rating had only come in to practice in 1969. So movies were only just starting to push the envelope. Then comes a film showing a 12 year old child screaming vulgar words, stabbing herself in the crotch with a crucifix, then smothering her mother's face in the blood, vomiting green slime, etc.. not to mention the religious/blasphemous content in a time when doing so was much more taboo than modern times.

Many people left the theaters in tears, or with nausea. Look up post-screening interviews of people having just seen the film if you wish to understand the impact it had in 1973.

The novel implies it was Regan that desecrated the statue in the church. While it doesn't go into specifics, it's confirmed by Lt. Kinderman in the novel when he picks a piece of clay from one of Regan's artworks when he visits Chris and the analysis comes back confirming it's a match with the clay used for the desecration.

The Exorcist premiered on network television on February 12, 1980 as a CBS Special Movie Presentation, which director William Friedkin edited himself to pass muster with network censors, removing most of the blasphamous and obscene language and the sexual stunts. He employed Ellen Burstyn to redub her cursing dialogue and Friedkin redubbed two of the demon's lines using his own "demon" voice because he didnt' want to work with Mercedes McCambridge again after a falling out with her.

It is just another way to say "My God," or "I can't believe it."

It is never clearly shown or stated when Regan is possessed by the demon. Potentially, she has been possessed since the beginning of the movie, as the demon's influence has been felt as far off in Father Merrin's ruins dig in the Middle-Eastern regions. It's also possible she used the Ouija Board to summon the demon (who, at the time, is masquerading as the imaginary friend known as Captain Howdy) in an offscreen sequence because she was feeling lonely and the demon took advantage of her sadness and loneliness to trick her into inviting him into her physical body. Remember, Regan's parents are divorced and she is often left with assistants of her mother's while her mother herself is working long hours on a large movie production. Her father, who is never seen in the film, is in Europe fooling around with other women and seems to never have time for Regan or even cares about her, which is partially evident when she is in the hospital or bed-ridden, since he never appears throughout the movie as a result.

One possible interpretation is that the demon is mocking Karras for his lack of faith and his reliance on scientific methods. The demon knows that Karras is skeptical of the supernatural and wants to see tangible evidence of the demon's existence. However, the demon does not want to give Karras what he wants, and instead challenges him to use his own faith and willpower to confront the demon.

Another possible interpretation is that the demon is trying to manipulate Karras and make him doubt his own abilities. The demon knows that Karras is suffering from guilt and grief over his mother's death, and that he feels inadequate as a priest and a psychologist. By saying that breaking the straps would be too vulgar, the demon is implying that Karras is asking for something trivial and unworthy of the demon's power. The demon wants to make Karras feel that he is not worthy of the demon's attention, and that he is powerless to help Regan.

A third possible interpretation is that the demon is simply lying and trying to avoid exposing its weakness. The demon may not be able to break the straps, or may fear that doing so would alert the authorities and endanger its possession of Regan. The demon may also be afraid of provoking Father Merrin, another priest who is an expert on exorcism and who later joins Karras in the ritual. By saying that breaking the straps would be too vulgar, the demon is pretending to be above such a simple task, and hoping to deceive Karras and Merrin into thinking that the demon is more powerful than it really is.

One possible explanation is that Regan was already showing signs of possession around Halloween, and that her mother Chris did not want to expose her to the public or risk any harm to her or others.

Another possible explanation is that Regan did not feel like going trick or treating, or that she did not have anyone to go with. She may have preferred to stay at home and play with her Ouija board, which was the only source of companionship and excitement for her.

There is no real explanation except it is to scare the audience as well as show Merrin's state of mind, his paranoia at seeing Pazuzu again, or maybe it could be Pazuzu sending messages to him to bring him back for one more meeting.

Regan says she found it. It's possible that the previous owners of the house left it there. Or perhaps a friend from school brought it over.

If an innocent child who did no harm to anyone was able to be possessed and tormented by a demon; what hope does the rest of humanity have?

The Exorcist is a 1971 novel by American author William Peter Blatty, who also wrote the film adaptation. The movie spawned four sequels: Exorcist II: The Heretic (1977), The Exorcist III (1990), Exorcist: The Beginning (2004), and Dominion: Prequel to the Exorcist (2005). The book was re-released in 2011 with slight revisions.

The book by William Peter Blatty was inspired by an actual event, the supposed exorcism of a demon from a 14-year-old boy living in Mount Rainier, Maryland, USA. Blatty had read a news report concerning the boy, whose family had called in a priest after conventional medicine had failed to relieve him of various symptoms, including violent episodes and outbursts of foul language. The priest spent two months with the boy, during which he claimed to have witnessed him speaking Latin (a language the boy had no knowledge of) and moving across the room on his bed whilst sleeping. However, investigative journalist Mark Opsasnick researched the story after the film was released and could not find any record of a boy having lived in the house stated in the original news article in The Washington Post on August 20th, 1949. There had been a case in Cottage City, Maryland of an exorcism being performed on a boy who allegedly would spit involuntarily, growl when angered, and whose bed shook from time to time. Opsasnick concluded that this was the case which Blatty had read about and that the Mount Rainier piece was a fabrication. Interestingly, while Opsasnick had sought to prove the possession was real, the evidence he uncovered forced him to conclude that the boy was only mentally ill, and the possession story was the result of the boy's religious mother and grandmother, a credulous priest, and sensationalistic reporting in the media. Another priest present at the exorcism has stated that he never witnessed any of the behaviour the character in the book/film exhibited and that some of the behaviour he did see could have been explained in other ways, e.g. while the boy in fact did speak some Latin on a couple of occasions, he seemed to be repeating phrases the exorcising priest was reciting from the religious manual. Opsasnick's investigation is regarded as the final word on the case, he having gone more in-depth into the story than any other journalist before.

The novel upon which the film is based makes it clear that Regan is possessed by Pazuzu, a demon referenced in Syrian and Babylonian texts as being "the demon of the wind". While Regan shows the Ouija board to her mother, she names her "invisible friend" (presumably, the self-declared name of the demon in question) as "Captain Howdy". The real name of the entity who possesses Regan is never addressed in the script nor any scene of the film, and audiences unfamiliar with the scope of demonology tend to assume it was Satan. However, Father Karras takes issue with Regan claiming to be "the devil himself", suggesting that it is unlikely that Regan is, in fact, possessed by the devil.

Folklore says that demons, despite all the evil deeds and violence they influence people to commit, are actually very cowardly, so they choose a vulnerable target. Furthermore, in a scene deleted from the theatrical release, but re-inserted into the extended director's cut, Father Merrin and Father Karras have a brief discussion during a break in the exorcism of why the demon would choose, of all people, to possess a 12-year-old girl. The priests come to the conclusion that, rather than physical destruction being the demon's motive, it is in fact attempting to wreak spiritual havoc by causing people to doubt God.

Also it also shows that by making a young innocent girl into a monster, the demon was showing his true strength to people. He can take the most innocent looking creature, and make them into an ugly evil and vile monster.

What better way for a horror author or director to display just how evil their demon is, than to have him possess an innocent 12yo girl? Physically small enough, that you dramatically display the demon's amazing supernatural power, by writing scenarios where the possessed 12yo girl sends grown men right across the room with a slap. But not so small that such a display seems comical, like it would to have a baby or toddler send an adult flying, like that.

12yo actors also have more skills, to portray a challenging role like the possessed Regan, as the centre-piece of a whole movie. Casting a younger child would better communicate "corruption of innocence", but they'd also lack the acting skills that Linda Blair showed, both with pre-possession Regan, and Regan under the demon's control.

This is from the Wikipedia entry for Demonic Possession: (1) The ability to curse/blaspheme/speak in languages unknown to the person; (2) the ability to find secret things, read the mind, and divine future happenings; (3) the ability to make physical efforts abnormal for that person; and (4) the act of spitting or vomiting every object the demons would have made the person swallow. For most of the movie, Father Karras is not completely convinced the possession is genuine and even states so at one point. For a portion of the movie, the girl's mother also attributes a lot of the behaviour to the girl and not a possessing influence. The only reference by either priest to symptoms is "speaking in a language she never learnt". Much of this behaviour is shown onscreen, with the unspoken implication that it is the result of the possession; none of the behaviour exhibited is directly and specifically attributed to the demon.

There is no clear reason given for this. One interpretation is that the demon wished for an encounter with Merrin in the form of a confrontational exorcism. In order to do so, the demon would do anything to make this a reality. It didn't know that the water wasn't blessed, but reacted as though it was, in order to convince Karras of possession. This analysis presents some conflicting issues, though. Another interpretation would be to confuse Karras and validate his impression that Regan was not possessed. The demon didn't want Karras to perform the exorcism (though it taunts him to do so, knowing full well he doesn't want to perform it, therefore traumatizing Karras for his lack of faith), but wanted Merrin to arrive for the fateful confrontation. The demon seemed to know a lot, including Karras's mother recently passing away and his recent contact with a nameless homeless man ("Can you help an old altar boy?"). According to Father Merrin, "It will mix lies with the truth in order to confuse us". Uncertainty is the premise of the entire movie, and so is the question of faith, so it would seem that the reaction to the tap water is an attempt by director William Friedkin to further the confusion.

It is also likely that the demon reacted this way purposefully to make the Catholic Church wary of performing an exorcism, as it wished to stay inside of Regan.

Many demonologists believe in three observed stages of demonic attack. First, Infestation brought on by calling upon demonic forces, whether intentional or not. Initially a demon may only scratch at walls, so as to mostly go undetected. Secondly, oppression, in which demons systematically oppress humans, often those who are the most emotionally vulnerable. Finally, if a demon has not been exorcised and its victim has been thoroughly tormented to the point where all their mental barriers against it have collapsed, the demon may execute fully-fledged possession. None of this is detailed in the movie. The noises in the attic, among other things, go unexplained.

Although it's never confirmed, the novel implies that Karl was the one who put the crucifix under Regan's pillow. Author William Peter Blatty also revealed in an interview that Karl (Rudolf Schündler) put the crucifix under the pillow because he is Catholic. Its appearance seems to be little more than a MacGuffin, escalating the demonic (read: blasphemous) behaviour of Regan and creating a seemingly legitimate reason to bring the priests into the main plot: Chris MacNeil had been hitherto reluctant to turn to religion to help Regan.

In the first half of the film, the demonic voice that comes from the possessed Regan is mostly Linda Blair's own voice, albeit heavily distorted. Actress Mercedes McCambridge also provides some lines, while most of the vocal effects and a few extra lines are done by Ron Faber. After the crucifix masturbation scene, Regan is voiced entirely by McCambridge until she is freed from her possession at the end of the movie. It was initially intended for Blair to provide the demon's voice all the way through, but after some testing, William Friedkin felt that the adolescent Blair did not have enough power or depth in her voice, so McCambridge was brought in. Warner Bros initially kept McCambridge's involvement quiet as to not take away from Linda's performance.

No. The physicians initially diagnosed a "disorder of the nerves", which quickly changed to a diagnosis of "a lesion ... on the temporal lobe of the brain" after further assessment of her behaviour. When nothing showed up on the following x-rays and arteriograms of Regan's brain, she was referred to a psychiatrist. A group of them diagnosed the condition as "somnambuliform possession" and recommended that Chris seek out an exorcist; the reason they gave was that believing oneself to be possessed can sometimes be cured by believing that exorcism works. What was actually going on inside Regan was left open to the reader to decide (in the novel), although it was for the most part suggested that she was possessed. On the other hand, the film makes it clear that she is actually possessed by showing such humanly impossible things as a head that can turn itself in a complete 360 degree rotation, a levitating bed and—later—body, sliding armoires, slamming doors, etc. But most important of all, the demon is seen to exchange bodies, leaping into Damien Karras at his demand. When he is possessed, Damien's irises turn a yellowish green, just as Regan's had while possessed.

There were nine deaths associated with the film, among them actor Jack MacGowran (who played Burke Dennings), Max von Sydow's brother, Linda Blair's grandfather, and a nightwatchman working on the set. However, the sheer number of people involved in the making of this film and the length of time it took to complete it made it more likely that some people connected with the film, however loosely, would die during its filming. There is nothing supernatural about it and crew members die all the time while making movies. They just happened to die during a horror film.

Back in 2001, an extended cut (later retitled Extended Director's Cut) of William Friedkin's cult movie was release that features nearly 10 minutes of new and extended footage, like the examination scene at the doctor's office or the famous "spider walk" sequence. Besides these newly integrated scenes, digital effects (such as the demon's face that appears as flash cuts in some scenes) were added and a newly composed score was used. Three scenes intended for inclusion in the Director's Cut were left out at the last minute due to lost prints/tracks: (1) A scene in which Chris MacNeil takes Regan on the promised tour of the city was left out when the soundtrack couldn't be found. (2) Another scene showing possessed Regan out her room, this time scurrying about on all fours licking peoples' ankles, was left out when the original negative couldn't be found. (3) An extension to the final scene, a continuation of the conversation between Kinderman and Dyer involving more movie references, was left off due to the sound of passing traffic in the background making the dialogue unrecoverable.

The Exorcist Enhanced Script Presentation includes highlighted dialogue and over 400 screenshots in sync with the story.