This film, based on the book of the same name which was written by Wade Davis, (a Canadian anthropologist) has some truly nightmarish scenes and isn't for faint hearted viewers.
It begins with a flashback to 1978. A Haitian man named Christophe Durant (Conrad Roberts) is pronounced dead then buried. Seven years later a U.S. scientist, Dr. Dennis Alan (Bill Pullman) discovers that Durant is alive. It is thought that a powerful drug had caused Durant's "death" and Dr. Alan is asked by a big pharmaceutical firm to go down to Haiti and investigate.
His Haitian contact is Marielle Duchamp (Cathy Tyson) and together they try to track down somebody who can provide them with a sample of the so called "zombie powder" which can totally paralyze a victim and fool a physician into thinking that the person is dead, but when in fact they are alive but unable to speak, or to move. This is something that Dr. Alan learns with terrifying clarity later in the film.
The Haitian secret police headed by Dargent Peytraud (Zakes Mokae) make it clear to Dr. Alan that they don't want him in the country, and Peytraud has no reservations about torture either. Little does Dr. Alan know that he is a bokor, an evil voodoo priest who has the power to take the souls of deceased people.
Duchamp and Alan are successful in locating a man who can help them find the noxious powder. Louis Mozart (Brent Jennings) shows Dr. Alan how it is made and he gets a rare look at how Haitian voodoo and magic are interconnected and its importance in the country. In Haiti, voodoo is a faith more widespread that Roman Catholicism. Extremely toxic ingredients are combined to form a powder that can be absorbed through the skin, and it is all brought together with a mystifying net of sorcery that would baffle North American scientists.
The line between the real world and the world of black magic starts to blur when Dr. Alan begins to experience disturbing nightmares. Probably the most horrific scene in the film is when he is sealed in a coffin that is filling with blood. Peytraud has the power to enter his dreams and gives one last warning to leave Haiti, or else.
Back in the States, but still unsettled by his recent experience Dr. Alan tests the powder and it confirms what he suspected. It can slow the human metabolic rate to such a degree that a person would have no discernible heartbeat or respiration. After 12 hours the victim would be completely normal again, but he/she might be buried deep in the ground.
Dr. Alan unwisely returns to Haiti to confirm the safety of Duchamp, but is exposed to the zombie powder himself. The scene in which Peytraud is standing over him in a clinic, and then above a grave is especially unnerving. He is lowered into the ground and finally when the drug wears off his screams echo throughout the deserted cemetery. An unlikely saviour digs him out, Durant. Dr. Alan then sets out to defeat Peytraud by using his magic against him. At the same time, the Haitian dictator "Baby Doc" Duvalier is ousted and flees the country and the locals are seen rejoicing in the streets.
The Serpent and the Rainbow was filmed in 1988 and due to the shaky political climate in Haiti at that time, the cast and crew completed the movie in the Dominican Republic since their safety in Haiti could not be guaranteed.