In shamanic culture Mapacho and other forms of tobacco are often used as a way to clear energy. The understanding of this really starts with more of an understanding of how a shaman would generally interpret nature. For a shaman there is a thin line between this world and the spirit world, and all living organisms have a spiritual essence to them, as well as a physical one. The shamans job is to communicate between the worlds to understand the properties of specific spirits and then bring back these ideas for personal healing, world healing and/or the healing of the people they are working with. So when a shaman sees tobacco, it is not just the physical substance, but a spirit that accompanies it.
There is no doubting that nicotine is an addictive substance and Mapacho in particular has a very high quantity of nicotine in comparison to other types of tobacco. However, the fact that something is addictive does not take away from the fact that it could have healing properties- making it both addictive and beneficial.
Mapacho is a contradictory medicine in the fact that it works as both a stimulant and a relaxant. Shaman often use it for help with setting intentions and for awakening the mind while still being able to ground that awakening.
Tobacco has been extensively studied by the scientific community, showing all the dangers that arise from its use, but the problem with these studies is that for the most part- they have been done on tobacco in the west, in the form of cigarettes. Most tobacco in the west is mass produced and grown with pesticides and other nasty chemicals, plus when they are produced further additives such as cyanide and arsenic (both deadly in bigger doses) are thrown into the mix to help them burn. In effect the studies are not being done on tobacco, but the end product which includes tobacco.
How It Is Administered As A Medicine
There are many different way tobacco is administered in a medicinal sense- the first to speak about is a tobacco purge: In a tobacco purge a high dose of mapacho tobacco is turned into a drink, which when consumed causes you to violently purge. There is a fine line between high dose and a lethal dose, so this is to be done only with a competent shaman.
A purge is used to clear energy, parasites, fungus and other pathogens from your system. It is also for grounding, which in a metaphorical sense is like deeply planting your roots in the ground. During the purge you will often feel weak, sick and break into a sweat. Vision can also be experienced. The purge is an ordeal and very uncomfortable, meaning you go through a traumatic purge knowing you will feel better afterwards.
Rapé is a mix of tobacco and often other substances which can be highly guarded secrets of the shaman. Rapé is administered using a snuff pipe and involves two shots of tobacco into the nasal cavities.
Rapé is used to cleanse yourself of negative energy, as pain relief and is known to stimulate detoxification. Many shaman claim that rapé decalcifies the pineal gland, which is the gland that produces DMT.
Used in conjunction with plant medicines such as ayahuasca- Mapacho smoke is often smoked by participants and also blown on them by the shaman during ceremony. It is also used for smudging or clearing energy of a person before, during or after a ceremony. It is also used for protection from bad spirits.
There is no hard conclusive evidence I could find, however, there is some links between properties found in tobacco and health benefits such as:
Tobacco (and ayahuasca) contains beta-carbolines, such as the harmala alkaloids harmane and norharmane- in a 2005 study on mice it was found that these properties contain a “an antidepressant-like effect”.
Also due to the Harmala alkaloid it is though that tobacco leaves could have anti-cancer properties- I know this goes against everything we have ever been told- but a 2005 study on dried powdered seeds of Peganum harmala Linn and leaf of Dracocephalum kotschyii Boiss showed that it can effectively kill some cancer cells in mice.