Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
This is not a snake movie. I watched it because I'm a fan of Ingmar Bergman's films and this is one of his masterpieces. I was surprised to see a brief scene with dead snakes used for magic. (Even better are the poisonous toad sandwich scenes.)
Ingiri, a servant girl, goes into a jealous rage then freaks out because she's afraid to be in the forest. To get rid of her, her mistress Karin leaves her at the house of an old one-eyed toothless shaman who has a creek pouring through his living room. He says he can help Ingiri. He takes a dried up finger, a bat, and a couple of dried up coiled snakes out of a box, saying the snakes are "a cure for your anguish and a cure for your woe." Given how tragically the rest of the movie turns out, I'd say the dried snake remedy didn't cure anyone's woe.