In relation to Ayahuasca, and in general within Amazonian or Central American traditional plant medicines and healing practices, you will often encounter the phrase Master Teacher Plant.
It refers to the intake of preparations of (parts of) certain medicinal plants or trees (such as Sanango, Coca, Chacruna, Mapacho, and Ayahuasca, among many others) of which some contain psychoactive properties. It’s thought that Master Teacher Plants reveal knowledge and wisdom to the user about their healing capacities through dreams, intuition, visions, and perceptions.
It’s also said that these Master Plants or Teacher Plants guide, support, or enable profound introspection to those who consume them, and additionally impart (sacred) knowledge about the world, nature, and the universe.
Master Plants may also be used to prepare for hunting or war, for revitalization, for divination, to see past and future events, to communicate with the ancestors and spirit world, and to cure various physical, psychological, and mental diseases, such as rheumatism, respiratory diseases, bone injuries, inflammations and infections, fears, emotional trauma, and spiritual afflictions, among a broad range of other conditions.
The teaching of these Master Plants is typically imparted to the user through dreams, visions, and Icaros (magic medicine songs), which are the result of following a certain Dieta (a Spanish word, and involving a kind of fasting), usually called the Plant Dieta, Teacher Plant Diet, or Shamanic Diet. This diet may be observed for a week, sometimes for months or even years depending on its aim, and is traditionally done in isolation, in the jungle.
With regard to Ayahuasca retreats, for instance, retreat facilitators or Shamans often suggest or advise the visitors to follow such a Dieta for a specific period before the actual Ayahuasca intake during the retreat ceremonies. This serves as a physical and mental preparation, cleansing, purification, and detoxification practice to benefit optimally from the workings of the Ayahuasca brew, while also building up the necessary energy to follow or “endure” the ceremonies.
The Dieta itself consists of a range of abstinences with regard to foods and drinks, such as not consuming alcohol, coffee, red meat, fats, salt, and sugar, while eating only a limited set of bland products, such as rice, cooked green bananas, or oats, etc.
Of course, apart from the above, the person who follows the Dieta will regularly ingest the specific Teacher Plant assigned to them, the latter typically suggested and prepared by a Shaman or Curandero. The Dieta may also involve regular purging by taking in purgative plants.
And finally, there are often some specific behavioral restrictions required during the fasting period, such as abstinence of sexual activity, exclusion of the use of beauty products, and avoidance of physical contact with others.