The Serpent and the Rainbow (1988)

Dennis is a Harvard anthropologist and is called up by his old professor with a job for a pharmaceutical company. He is to go to Haiti and investigate the rumors and folklore of zombies. A man who died 7 years earlier, was found wandering in the village. He is to go there, and find out how he has come back to life. Dennis goes to Haiti, and meets Marielle, a doctor who treats the mentally ill, and since zombies have no control over themselves, she gets a lot of them. Dennis and Marielle go on investigating, and they find out, people are turned into zombies through a powder through the skin. Dennis is a scientist, and doesn't really believe this. Little does he know, there are things about this voodoo powder that science will never know. All of this is going on as a strict dictatorship is running Haiti. The leader does not want Dennis investigating this. It is rumored he is a powerful black magician. What will Dennis learn after his decent into a mystical, dark world in Haiti?