A witch doctor is a traditional, magical healer who specializes in preventing and treating maladies of magical or supernatural origin, including, but not limited to, those believed to be caused by witchcraft.
Although the term is generally heard with regard to the more “primitive” cultures of Africa and South America, it is very much an English term first used for European practitioners of the art and then applied to these other cultures by European observers. In Europe, practitioners may also be referred to as cunning folk, though this is a more general term.
Native practitioners have their own terms for these specialists and the term “witch doctor” is rarely sufficient.
In South Africa the term witch doctor is often applied by English-speakers to the Sangoma (Zulu) who specializes in identifying supernatural causes of problems and prescribing correct actions to bring about spiritual balance needed to rectify the problem.
In West Africa a Juju Man (or woman) may be consulted in matters of health and spirit as well as personal matters. These practitioners can use divination to answer questions or solve problems of luck and health and prescribe rituals and charms to solve their clients issues. Juju men can also be found in many of the African descended communities scattered throughout the Western world by the slave trade-induced diaspora.
The Nganga are traditional healers of Zimbabwe. They are both healers and spiritual counselors who use a combination of ritual, herbal lore and consultation with spirits to help their clients in all manner of things, especially health.
In Central America, the Curandero (“healer”, Spanish, Portuguese) do similar work. There are many types with different specialties who work to relieve symptoms caused by unsettled spirits and curses and to protect the vulnerable from these using rituals, herbs and other methods.
Bomoh in Malaysia consult spirits to assist their clients and identify elemental imbalances to bring about health and wellness.
Many of these would be more accurately called shamans than witch doctors, though these two terms are often erroneously used interchangeably as well.
In modern vernacular, the phrase “witch doctor” has come to be used in a derogatory manner to refer to a person who victimizes people desperate for a cure by giving them false medicine at high cost.