Once upon a time, cinemas screening "The Exorcist" handed out barf bags to their patrons as a cheap gimmick. (The movie was so "sick" it would make you sick.)

These days, however, cinemas might be needing them for real: A small but significant number of moviegoers with motion sickness are having an increasingly hard time stomaching shaky camerawork and hyperfast CGI camera sweeps on the big screen. Some movies are, quite literally, making people feel ill.

Fortunately, there's a cranky website called Movie Hurl that rates films solely on their ability to make you feel nauseous, with "Birdman" and "Hunger Games: Mockingjay" amongst recent offenders.

The website is right to claim that this is a recent problem. I recall first hearing about it with regards to 1997 drama "Breaking the Waves," while Movie Hurl references 1999 horror "The Blair Witch Project"; both films were shot on handheld video cameras. Director Paul Greengrass — who helped bring rough, on-the-fly documentary-style camerawork to the giant screen — is also targeted by Movie Hurl, especially for his films "Captain Phillips" and "The Bourne Ultimatum."

The problem (for some people) seems to stem from the brain's inability to process frantic movement that is being received optically while the body remains still. Indeed, the makers of virtual reality entertainment for devices such as Sony's PlayStation VR are grappling with this very issue.

Whatever the case, if you suffer from motion sickness and you're thinking of trying "4-D" cinema, you might want to bring a bag.