33 Gross As Heck Scary Movies That’ll Leave You Feeling Ill

Horror movies intentionally provoke terror and fear by design, poking at our primal lizard brains to trigger physiological reactions our bodies developed over eons to help us survive. Given that your brain and body think the stakes are life and death, it's understandable that some people don't enjoy watching the genre. But some horror movies do far more than just scare on an adrenal level — part of the full fright spectrum includes dredging up feelings of repulsion, revulsion, and queasiness. These 33 scary movies that may make you sick aren't for the weak of heart or stomach; most are on record as having audience members become ill or need to leave the theater during screenings.

A number of the films on this list use audio to physically mess audiences up — as mentioned, our bodies are wired for survival, and sounds falling below 19 Hz (known as "infrasound") or jarring high-pitched noises (like animals in distress, or women and children screaming) trigger physical reactions of dread and nausea, per Atlas Obscura. According to 1998 research paper called "Ghosts In The Machine" (via Gizmodo), infrasound may even be responsible for ghost sightings.

Other films lean heavily on bodily fluids and gore to trigger the same responses — you don't need a soundtrack to feel sick seeing creatures slithering into wounds or bloody viscera spattered everywhere. But for those brave few who want to wallow in the corporeal, these 33 films are for you.

1. 'Cannibal Holocaust'

This is a movie so infamously gory that its director was arrested for obscenity and so convincingly creepy he was also put on trial for murdering his performers, according to The Guardian's oral history of the film. (He was released when the perfectly alive and safe actors showed up at trial.)

2. 'Zombi' (a.k.a. 'Zombi 2')

Helmed by an Italian horror director best known for his signature eyeball-gougings, Zombi 2 is a sequel to Zombi, a Dario Argento re-edit and re-score of George Romero's Night Of The Living Dead. This film ups the gore and features many a corpse being consumed.

3. 'Irréversible'

Director Gaspar Noe admitted to using infrasound to intensify the already disturbing story, which Roger Ebert called "a movie so violent and cruel that most people will find it unwatchable."

4. 'Raw'

This tale of a vegetarian veterinary student growing a taste for meat caused Toronto International Film Fest viewers to pass out at its premiere, according to CTV News.

5. 'Dead Or Alive'

How bloody is this film? Peter Jackson's bonkers and extremely gory take on zombies includes an infamous scene with a roomful of bodies and an inverted lawnmower, for one.

6. 'The Green Inferno'

If you're noticing a trend, a lot of these films are focused on cannibalism; we're not used to thinking of ourselves as part of the food chain. Director Eli Roth used that revulsion to his advantage, capturing audience reaction to his eco-samaritans caught in the Amazon and using it as sales campaign.

7. 'Nekromantic'

A film that thoroughly explores every possible taboo of human remains, including disfiguring, eating, and sleeping with them (after all, at heart, it's a love story).

8. 'The Human Centipede'

The campaign for this movie began and ended with its basic concept, which director Tom Six explained to Vulture started as a "joke" about what should happen to an accused child abuser he saw on Danish television. And it went on from there!

9. 'Saw III'

Oddly, it was only this entry in the Saw franchise that, according to the Guardian, required ambulances to treat audience members in theaters — at over two hours, maybe the difference was just the sheer volume of torture?

10. 'Freaks'

Tod Browning's tale of revenge cast actual circus performers (the "freaks" of the title), and the un-PC nature of gawking at deformity reflected more on viewers' discomfort than exploitation on Browning's part. Mental Floss notes MGM wouldn't even let the performers eat in the shared cafeteria while filming.

11. 'Goodnight Mommy'

When their mother returns after facial surgery, her twin sons come to the conclusion the person under the bandages isn't actually their mother... and they're willing to get under her skin to find out for sure.

12. '127 Hours'

Not a horror film in the traditional sense, this true-life tale of a hiker caught beneath a boulder who comes to realize his only hope for survival is severing his own arm is definitely its own kind of endurance test.

13. 'Revenge'

A modern take on '70s rape-revenge films, including I Spit On Your Grave and Last House On The Left, the main updates here are sharper imagery and better gore effects.

14. 'V/H/S'

The Daily Mail claims it was the gore that made Sundance audiences sick, but seems that the shaky, handheld verité camera style had a lot to do with it as well.

15. 'Salo Or The 120 Days Of Sodom'

A Criterion essay for this film describes it as "the cruelest, most obscene, and most intellectually toxic work ever made by a major director," noting that filmmaker Pier Paolo Pasolini wanted to make a work that was "indigestible." Based on a work by the Marquis De Sade and exploring the full depths of human depravity, Pasolini's tale of Fascists torturing innocents was damning criticism of his native country, and may have even resulted in his own suspicious death.

16. 'Bite'

This story of a bride-to-be's post-bachelorette party insect bite infection and its resulting transformations caused Fantasy Fest audiences to puke and pass out, according to First To Know.

17. 'Van Dieman’s Land'

Yet another cannibal film, this one is based on a real-life Australian tale of escaped convicts who eat each other to survive.

18. 'The Perfection'

In the streaming era, people took to Twitter to complain this film seemingly about competing cellists made them nauseous and ill.

19. 'Street Trash'

A Brooklyn liquor store owner decides to sell spoiled 60-year old alcohol to the winos in his area, causing anyone who drinks it to melt into a pile of goo. In an archived National Board of Reviews interview, writer Roy Frumpkes said, "I wrote it to democratically offend every group on the planet."

20. 'Antichrist'

According to The Guardian (who seems pretty up-to-date on illnesses in theaters) audiences "yelped and howled and covered their eyes. Legend has it that at least four viewers fainted dead away in their seats" at the Cannes film festival.

21. 'Ichi The Killer'

For the A.V. Club, reviewer Scott Tobias wrote, "The first 15 minutes of Ichi The Killer tested my flight-or-fight instinct like no other movie I can recall." That's either warning or seal of approval, depending on your constitution.

22. 'The Devil’s Rejects'

It's a gruesome, unrelenting film that actually invests in its characters. The Nashville Scene reported that The Devil's Rejects went through 8 MPAA screenings with an NC-17 before finally getting down to an R, after cutting over two minutes from an infamous motel scene.

23. 'Contracted'

After having unprotected sex, a young woman begins to realize she's got a lot more than VD to worry about.

24. 'The Fly'

David Cronenberg's visceral take on the 50s horror classic is all about the failure and formation of the body.

25. 'Slither'

Finally, a film about alien parasites instead of cannibalism! The scene where the police finally find local woman Brenda swollen with alien larvae is a gross-out high point.

26. 'Re-Animator'

Body parts are flung with abandon in this adaptation of H.P. Lovecraft's story about a young man obsessed with reanimating the dead.

27. 'The Snowtown Murders'

Australia, what is going on? The second movie on this list featuring a true crime story from the continent, this one is unrelentingly grim and more disturbing than gory. The crimes leave you feeling nauseous, as there's no explanation for the evil.

28. 'Ravenous'

OK, back to cannibalism. This surprisingly funny tale has two cannibals facing off on the fringes of civilization — one enjoying the powers and nigh-immortality that come with chomping on fellow humans, the other determined to stop him.

29. 'Martyrs'

Never properly released save on DVD in the U.S., this extreme of Extreme Cinema pushes every boundary. It's a straight-through unrelenting barrage of tension and anxiety... and that's before the torture kicks in.

30. 'Cabin Fever'

Nothing like a flesh-eating virus to let a film really stretch its imagination in depicting the various ways bodies can disintegrate.

31. 'Ebola Syndrome'

...But why make up a flesh-eating virus when there's a real version? This video nasty features gore, depravity, cannibalism, casual racism, and some truly gruesome scenes, including grinding a family up into hamburger patties and serving them to the public.

32. 'A Serbian Film'

An aging porn star signs a Faustian bargain that will leave his family financially secure, but him at the whim of a sadistic director. The film was banned in several countries, per CBS News, and (similar to Salo) is supposedly political commentary on his country's atrocities in the Balkans.

33. 'Trouble Every Day'

This gory tale of two couples each coping with one member's taste for flesh shocked Cannes audiences when it came out. Said Claire Denis to The Guardian, "It's about desire and how close the kiss is to the bite. I think every mother wants to eat her baby with love. We just took this on to a new frontier."

If you don't feel queasy having read through this list, then you've probably got the stomach to watch a film or two from it. Just... not right after a meal.