Excerpted from an article by E. Wade Davis in the November 1983 issue of the Journal of Ethnopharmacology. A fuller account of Davis’s search for the Haitian zombie poison was documented in The Serpent and the Rainbow, published by Simon & Schuster. His Into the Silence: The Great War, Mallory, and the Conquest of Everest was released by Knopf in 2011.

The anthropological and popular literature on Haiti is replete with references to zombies. According to these accounts, zombies are the living dead: innocent victims raised from their graves in a comatose trance by malevolent voodoo priests (bocors)…