Trivia: During the feast in which Christian finds a pubic hair inside of his food, look closely at the drinks on the table. While the camera never calls direct attention to this, if you look closely, Christian's drink is very slightly darker than everyone else's. Earlier in the film, the camera briefly passes over a mural that depicts a woman collecting menstrual blood in a cup. (Along with the image of a woman cutting off pubic hairs, like the one Christian found in his food.) It seems Christian's drink has been laced with something he didn't expect.
Trivia: Near the end of the film, as Dani is lifted and being carried to the dinner table, if you look closely, you can see the ghostly image of her deceased sister's face (with the exhaust hose in her mouth) in the background. It's been superimposed over the trees in the distance. It's very subtle and easy to miss, but if you know where to look, it's there.
Trivia: Jack Reynor himself suggested that he run away nude after the sex scene. He was originally scripted to have grabbed a robe. Reynor felt this would make him look more pathetic and vulnerable. He also reportedly was influenced by seeing numerous women in horror movies run around naked, be sexually assaulted, etc. He felt it only made sense that male characters should also be forced into similar compromising and undignified situations.
Trivia: Throughout the early scenes, Dani's clothing is all loose, ill-fitting or otherwise unflattering. However, when she is given clothes by the cult, they all fit her perfectly. It has been widely speculated that this is a very subtle hint that she fits in better with the cult than normal society.
Trivia: The flower dress Dani wears at the end of the film took weeks to build, and included over 10,000 artificial flowers. The crew wanted to use real flowers, but it would have been impossible to keep them all alive. It was reportedly incredibly heavy and unwieldy, and actress Florence Pugh could barely move in it.