Horror film Midsommar leaves terrified viewers unable to sleep

This was one of Herald Entertainment's most read stories in 2019.

A horror film that has been hailed by critics as a thrilling masterpiece has left some audience members feeling violently ill and unable to sleep.

Midsommar is director Ari Aster's follow up to last year's critically acclaimed debut, Hereditary, starring Toni Collette.

Set during a nine-day pagan festival in Sweden, Midsommar has earned several five-star reviews from critics, including The Telegraph's Tim Robey, who called it "heroically upsetting".

"Sick but also beautiful, the film gets away with an impressively audacious running time, simply because it can. It dazzles you with dread," writes Robey.

Even the film's stars were traumatised by the final cut, with actor Will Poulter telling Vulture: "I was so f***ed up after watching it that I didn't sleep. It's maybe the most aggressive reaction I've ever had to a film."

Likewise, viewers have reported extreme reactions to the horror since it opened in cinemas, with many saying they were unable to sleep.

The film follows the story of an American couple on the rocks who decide to join a group of friends on a trip to a midsummer festival in an isolated Swedish village.

Set during the summer solstice, the film takes a sinister turn as the villagers involve the visitors in increasingly disturbing rituals.

The film's official trailer reveals graphic glimpses of disembowelment and violence, with all the horror carried out in broad daylight.

Meanwhile, some fans found the film to be a deeply moving experience away from the horror.

Aster made his directorial feature debut with Hereditary last year, which earned widespread infamy as one of the scariest films ever released.

Midsommar will be in New Zealand cinemas from August 8.