The script by Richard Maxwell and Adam Rodman is loosely based on the non-fiction book of the same name by ethnobotanist Wade Davis, wherein Davis recounted his experiences in Haiti investigating the story of Clairvius Narcisse, who was allegedly poisoned, buried alive, and revived with an herbal brew which produced what was called a zombie.

In 1978, a Haitian man named Christophe mysteriously dies in a French missionary clinic, while a voodoo parade marches past his window.

Seven years later, Harvard anthropologist Dennis Alan is in the Amazon rainforest studying rare herbs and medicines with a local shaman.

He drinks a potion and experiences a hallucination of the same black man from Christophe's funeral, surrounded by corpses in a bottomless pit.

Back in Boston, Alan is approached by a pharmaceutical company looking to investigate a drug used in Haitian Vodou to create zombies.

Alan's exploration in Haiti, assisted by Dr. Marielle Duchamp, locates Christophe who is alive after having been buried seven years earlier.

Continuing his investigation, Alan finds a local man, Mozart, who is reported to have knowledge of the procedure for creating the zombie drug.

Alan is arrested again by the Tonton Macoutes, and tortured by having a nail driven through his scrotum, and then dumped on a street with the message that he must leave Haiti or be killed.

Its consensus reads, "Although it's occasionally overwhelmed by excessive special effects, The Serpent and the Rainbow draws on a chilling atmosphere to deliver [an] intelligent, politically informed story.