By attaining a trance state at will, the shaman is believed to be able to communicate directly with the spirits. The Ayahuasca drink's psychoactive properties are thought to derive from the presence of a psychedelic compound called DMT. Many believe that the ayahuasca experience results from communicating with the plants' spirits. Shamans who work with spirits of the plants -
https://dmt.vision/articles/101/ - insist that the plants are assisting us in our evolution and provide the necessary guidance.