The Serpent and the Rainbow is a 1988 American horror film, directed by Wes Craven and starring Bill Pullman. The film is very loosely based on a non-fiction book by ethnobotanist Wade Davis, dealing with his experiences in Haiti as he investigates the story of Clairvius Narcisse, allegedly poisoned, buried alive, and given a herbal brew whose effects mimicked zombification.

Synopsis
Dennis Alan, an ethnobotanist/anthropologist from Harvard University, narrowly escapes the Amazon Jungle at the beginning and returns to Boston. Word of his exploits gets around and he is approached by a large pharmaceutical corporation looking to investigate a drug that is part of the Voodoo religion in Haiti that they want to acquire in order to mass produce. They send him to Haiti to find out about the drug, but he winds up learning more about zombification instead. In essence, the drug is an alternate and less dangerous method of anesthesia.

When Alan arrives in Haiti the country is in the middle of a revolution of sorts. The government is taking anyone prisoner who they think is against the current political powers. He eventually meets another doctor who helps him research and investigate the so-called zombies. What he finds is the evil that lurks behind the Voodoo religion and the destruction it can cause to the human mind.

Background
The drug named in the film is tetrodotoxin. In the real-life "zombification" case of Clairvius Narcisse of Haiti, the poison that caused the appearance of death was reported to be tetrodotoxin, but the mind-control drug given after he was unburied was a brew derived from Datura stramonium. The film depicted the poisoning attack with the powdered drug being blown into the victim's face, which is most consistent with involuntary dosing of scopolamine. Scopolamine is one of the alkaloids in Datura, known to facilitate behavior control, but not the appearance of death.