Your mother must wash socks in hell if you weren’t at least a bit grossed out by Regan vomiting over the man trying to exorcise her demon in 1973’s horror classic The Exorcist, and it wasn’t the only scene in this Oscar-nominated film that caused our stomachs to turn. Considered by some to be the greatest horror movie of all time, William Friedkin’s The Exorcist is based on a best selling book by William Peter Blatty, and follows the possession of a 12-year-old girl called Regan, and the attempts by her mother and two priests to exorcise her.

The story behind the movie is almost as shocking at the movie itself, so it’s with that in mind that we present the following 10 unbelievably shocking facts about The Exorcist…

10. It’s based on a true story

William Peter Blatty’s novel is based on a real life exorcism performed on a boy by a priest in 1949. The exorcism was one of only three to have been sanctioned by the Catholic Church in the US at the time.

9. Linda Blair read the book

Despite only being 12 years old when she was cast in the role of Regan, Linda Blair read the book the movie was based on to prepare for her role. When asked what the book was about, Blair said “it’s about a little girl who gets possessed by the devil and does a whole bunch of bad things.”

8. The set burned down

Filming of The Exorcist was filled with many strange tales of accidents and things going wrong, as not only did Linda Blair and Ellen Burstyn (who played Regan’s mother Chris MacNeil) both experience injuries, one of which we’ll come onto later, but most of the set also burned down. These and other on set troubles meant that the movie took twice as long to film as was planned, and it also ended up costing twice its initial budget.

7. William Friedkin slapped one of the actors

Director William Friedkin went to some extreme lengths to get intense performances from his actors, even going so far as to slap one of them. William O’Malley, who played Father Joseph Dyer, has made known that Friedkin slapped him hard across the face in an attempt to generate a more solemn reaction whilst filming the last rites scene.

6. Friedkin often fired a gun on set

Other extreme methods taken by William Friedkin included firing blanks without warning to get genuinely shocked reactions from his actors. He also told actor Jason Miller that the ‘vomit’ would be fired into his chest, hence Miller’s genuinely shocked reaction when the pea soup hit him square in the face!

5. One of the sets was built in a freezer

These days, special effects companies are paid a lot of money to add computer-generated breath to actors so that scenes look colder than they are, but back in the 1970s they had to come up with other solutions. And in The Exorcist, Regan’s bedroom set was built inside a freezer to ensure that the actor’s breath would be visible on camera, meaning that the film crew had to wear cold weather gear!

4. Ellen Burstyn broke her back filming one scene

In a shot that even made it into the final cut, Ellen Burstyn was pulled to the floor by a cable after Regan slaps her across the face. The stunt had gone well in previous takes, but director William Friedkin wasn’t happy with what he was seeing, so told the man pulling the cable to pull it even harder. That is exactly what happened, and Burstyn’s subsequent fall broke her tailbone, with her cry of pain in the finished film being absolutely genuine.

3. Some cinema-goers suffered physical reactions upon seeing the film

It was reported that a number of cinema-goers suffered physical reactions after watching The Exorcist for the first time. There were several reports of people fainting and vomiting, and even experiencing cardiac arrests.

2. Some parents took their children to see it

Unbelievably, some parents took their children to see The Exorcist, and there were accusations that the US ratings board had been kind to movie studio Warner by giving the film an R instead of an X rating in an attempt to increase its box office. Some US cities even went so far as to try and ban it completely or at least stop children seeing it, and the controversy also meant that it was not given a home video release in the UK until the late 1990s.

1. It may contain subliminal imagery

Another reason that The Exorcist was deemed to be controversial was down to its alleged use of subliminal imagery. However, the images in question have been labeled as ‘not truly subliminal’, with The Exorcist author William Peter Blatty explaining that “there are no subliminal images. If you can see it, it’s not subliminal.”