There is to date only one real life documented case of a Voodoo zombie, which in some ways is a little disappointing, as considering how much we hear about them, you'd expect Haiti to be teeming with them. Haitian voodoo zombies, however, are not the undead flesh hungry killing machines we all love, but instead are simply the very nearly-dead brought back with a combination of natural ingredients which locks away their personality in a state of psychotic delerium that leaves their motor functions intact and directable by external instruction. Basically, mindless human robots, capable only of doing what they are told to.

It wasn't until Clairvius Narcisse wandered into his family home in several years after his death, which had been confirmed by a hospital, that proof of this process turned up. According to the story, Clairvius had been getting in the way of his brother's ambitions and had to go. His brother sold him as a slave to a Zobop Bokor (a special type of voodoo sorceror, sort of like a necromancer), on the condition that he was "removed". He was given a poison which brought his body to the brink of death and unhinged his mind. His family buried him, the Zobop Bokor dug him up and finished the process of turning him into a zombie, and then sold him to a sugar plantation. He remained there working long hours without rest until the owner died. Eventually Clairvius regained his senses and wandered away in a daze, over the next 16 years his memories returned and one day he bumped into his long-lost sister in a market place and recognized her. It was only through being able to recite things that had happened to them as children that he was able to prove his identity.

Part of the initial poison that paralyses and brings the victim to the brink of death to start the zombification process is a combination of toad skin and pufferfish. The toad skin itself can kill - as all toads are able to excrete a venom and their venom causes numbness in mild cases, and paralysis and death in the extreme. Pufferfish are delicacies in Japanese cuisine (fugu) and too much of their toxin puts you in a coma and reduces your body functions to a death-like state, even reducing the temperature of your body. It is not unheard of in rare cases for people to be declared dead after eating badly prepared fugu, only to revieve days later from a coma so deep that a doctor could not detect life signs. Because of the hot climate in Haiti, the dead are buried fast, and as long as the Bokor can dig the body up within 8 hours of the burial, he will be able to bring the unfortunate victim back, even if it has some brain damage due to oxygen deprivation.

The original poison has an additional side effect as mentioned of basically making the mind of the victim unstable and vulnerable to control. It's at this point that a strong dose of Datura is given. In small doses Datura is a hallucinagen and linked to religious "vision quest/spirit journey" rituals in various countries. In concentrated doses it's side effects become severe and leaves the subject in a mindless and easily directed state as it first breaks all links with reality and then blocks out all personal memory. So, the victim doesn't know what day it is, where they are and, worst of all, they don't even know that they're an individual. They can then be kept in a state of semi-permanent induced psychotic delirium by regular doses of concentrated Datura. It is thought that often the "dead" are not dug up soon enough to escape brain damage, and do not need much Datura to keep them controlled. Should their supply ever be cut off, they would never regain enough of their former self to be able to explain what had happened to them.

This fate is so feared in Haiti that it is not completely uncommon for people who have died suddenly and unexpectedly to be ceremonially stabbed through the heart by their families at the funeral.

Since these are "living" zombies, and not true undead, their physical bodies need to be kept alive as much as ours do. So, no brain eating & flesh tearing for them. Their violent tendencies are limited to the dangerous moments of revival after death, as the Datura paste is fed to them, when they have to be tied down due to the violent spasms they have when "awakening". In other words, it is unlikely that the Z day we all anticipate will come from Voodoo zombies, as they are passive and easily directed.

References: please be aware some may contain uncomfortable images/information.
http://science.howstuffworks.com/zombie.htm
http://en.wikipedia.org/wiki/Clairvius_Narcisse
http://en.wikipedia.org/wiki/Datura
http://en.wikipedia.org/wiki/Bufo
http://www.dhushara.com/book/med/zombie.htm

Further Study: please be aware some may contain uncomfortable images/information.
The Serpent & The Rainbow - Dr. Wade Davis - find it in our store.
The Passage of Darkness - Dr. Wade Davis - find it in ourstore.
http://www.archive.org/details/IanWoolfRealZombies_0