Belladonna, broomsticks and brain chemistry

Her blood is settled, and her joints are stiff; Life and these lips have long been separated. Death lies on her like an untimely frost Upon the sweetest flower of all the field. Romeo and Juliet, Act IV, Scene v. 

The most likely cause of the narcosis, disorientation and death-like state described in this passage from Shakespeare's Romeo and Juliet  were berries of the deadly nightshade Atropa belladonna, more commonly known as sorcerer's berries, devil's berries or murderer's berries. This plant and its relatives Hyoscyamus niger (henbane), Datura stramonium  (thornapple), and Mandragora officinarum  (mandrake) - all from the Solananceae family - are associated with the most interesting folklore of any plant. They were used by the Ancients to induce narcosis as an adjunct to surgery, and there was often much mystique associated with their collection - the ritual employed when uprooting a mandrake usually involved a dog tied to the plant and the collecting apothecary or necrophile had his ears blocked with wax.