According to the tenets of Voodoo, a dead person can be revived by a bokor or Voodoo sorcerer. Zombies remain under the control of the bokor since they have no will of their own. "Zombi" is also another name of the Voodoo snake god Damballah Wedo, of Niger-Congo origin; it is akin to the Kongo word nzambi, which means "god". There also exists within the voudon tradition the zombi astral which is a human soul that is captured by a bokor and used to enhance the bokor's power.

In 1937, while researching folklore in Haiti, Zora Neale Hurston encountered the case of Felicia Felix-Mentor, who had died and been buried in 1907 at the age of 29. Hurston pursued rumors that the affected persons were given powerful drugs, but she was unable to locate individuals willing to offer much information. She wrote:

"What is more, if science ever gets to the bottom of Voodoo in Haiti and Africa, it will be found that some important medical secrets, still unknown to medical science, give it its power, rather than gestures of ceremony." [4]

Several decades later, Wade Davis, a Canadian ethnobotanist, presented a pharmacological case for zombies in two books, The Serpent and the Rainbow (1985) and Passage of Darkness: The Ethnobiology of the Haitian Zombie (1988). Davis traveled to Haiti in 1982 and, as a result of his investigations, claimed that a living person can be turned into a zombie by two special powders being entered into the blood stream (usually via a wound). The first, coup de poudre (French: 'powder strike'), induced a 'death-like' state because of tetrodotoxin (TTX), its key ingredient. Tetrodotoxin is the same lethal toxin found in the Japanese delicacy fugu, or pufferfish. At near-lethal doses (LD50= 5-8µg/kg)[5], it can leave a person in a state of near-death for several days, while the person continues to be conscious. The second powder, composed of dissociatives like datura, put the person in a zombie-like state where they seem to have no will of their own. Davis also popularized the story of Clairvius Narcisse, who was claimed to have succumbed to this practice. There remains considerable skepticism about Davis's claims,[6] although there is wide belief among the Haitian people of the existence of the "zombie drug". The Voodoon religion being somewhat secretive in its practices and codes, it can be very difficult for a foreign scientist to validate or invalidate such claims.

Others have discussed the contribution of the victim's own belief system, possibly leading to compliance with the attacker's will, causing psychogenic ("quasi-hysterical") amnesia, catatonia, or other psychological disorders, which are later misinterpreted as a return from the dead. Scottish psychiatrist R. D. Laing further highlighted the link between social and cultural expectations and compulsion, in the context of schizophrenia and other mental illness, suggesting that schizogenesis may account for some of the psychological aspects of zombification.

See also: History of Haiti