Voodoo is an series of underground religious practices that were brought to Louisiana by African slaves sometime in the early 1700's. It bases its religious tenets upon ancient customs from Africa, and uses potions, charms, spells, and dolls to carry out its rituals.
One rather odd practice of voodism is using a voodoo doll to supposedly inflict harm or death to another person. They stick pins or knives into the doll, cast spells on it, and even burn it! Their belief is that whatever is done to the doll really happens to the real person!
While it's not certain if voodism really works, it's popular in the south and still practiced by many. In New Orleans, it's quite a tourist attraction.
Hoodoo (folk magic) is also prevalent in the south, but is more connected to witch doctors and black magic. Hoodism bases its beliefs, strangely, upon the Bible, and many hoodoo doctors believe they are called of God to perform their duties. These doctors use spells to cast out evil spirits which they believe cause any and all diseases, and potions made from herbs, animal parts, and body fluids to help cleanse and purify the body.
Both voodism and hoodism is very prevalent, even today, among the African American population of the deep south, namely Louisiana.