Macumba is a word of African (Bantu) origins. Various explanations of its meaning include "a musical instrument", the name of a Central African deity, and simply "magic". It was the name used for all Bantu religious practices mainly in Bahia Afro-Brazilian in the 19th Century. Later (20th century) these practices re-aligned themselves into what are now called Umbanda, Quimbanda and Omoloko. "Macumba" became common in some parts of Brazil and this word is used by most people as a pejorative word meaning "black witchcraft".
The word "macumba" is frequently used in Brazil to refer to any ritual or religion of African origin (as slang), and although its use by non-practitioners remains largely pejorative in intent (referring to all sorts of religious (or otherwise) superstitions and luck-related rituals and beliefs), and is considered offensive, its use among actual practitioners is not viewed negatively. In Brazil one can find expressions such as "chuta que é macumba" ("kick it out, for it is witchcraft!") to show disagreement with bad luck.
Macumba is also practiced in equatorial Africa, in particular in both the Republic of Congo and Democratic Republic of Congo, where there is some indication this "religion" originated. As the Bantu are found in the Congos, it is reasonable to assume it was transplanted by slaves from Congo to Brazil. While Macumba is related to "Voodoo" and shares several traits with its Western Hemisphere cousin, there appear to be some differences as the cult changed when brought to the New World.
As referenced earlier, Macumba is practiced in Brazil. As an example, in the Amazonian city of Santarem, Para State, there is a shop which sell materials related to Macumba in the central part of the city. One symbol of Macumba in Amazonas is that of a Black man wearing a white Fedora hat. There appears to be a relationship with the concept of the Boto (the fresh-water porpoise found in the Amazonas River and its tributaries) having shape-shifting abilities and then while in the form of a human male having sexual relations with young women. This belief was noted in several Indian villages along the Amazonas (Solimoes) River, Rio Negro and Japura River.
As an example of how Macumba functions, if a person desires to receive money, he/she visits a person or a shop specializing in Macumba, such as the one in Santarem. After paying a sum to the specialist, the person is then given a certain herb gathered in the jungle and is told to put the herb in bathwater and told to bath in it daily for seven days. The person utilizing the herb is then supposed to receive money thereafter. In Brazil it appears that males often are involved in the dispensing of Macumba knowledge/spells/materials.
As observed in the Republic of Congo in Brazzaville and the town of Dolise, Macumba is practiced by females exclusively, who were noted as having set-up tables in Poto Poto and sell various herbs to passersby. There is also a link to the usage of various jungle intoxicants by practicers of Macumba. In the Republic of Congo region of Pool, the rebel group called the "Ninjas" practiced Macumba, and in Kinkala the Ninja were said to have purchased and wore amulets from an old woman practicing Macumba which the Ninja believed protected them from gunshots.
It is difficult to pin-point exactly what Macumba is, as it includes a wide variety of beliefs and is not static or defined to any extent. In more remote areas such as villages along the Motaba River and Impfondo in the Republic of Congo, it would be somewhat different from that practiced in a more cosmopolitan city such as Santarem, Brazil. The only absolute statement which can be made in reference to Macumba is that in both Congo and Brazil Macumba uses plants and herbs gathered from the jungle and the knowledge of a person experienced in its usage to bring about an event or a desired effect for the person seeking to use Macumba.