They are used to enhance or subdue the effects of plant medicines, to evoke plant spirits, to invite the spirits of others or the deceased, to dispel dark spirits, or to protect those present, and to manage the ceremony. Experienced shamans can recite hundreds of icaros.
Icaros are either whistled or vocalised in words and vocables.
The singing or whistling of icaros is sometimes accompanied by chakapa, a rattle of bundled leaves.
- Pratt, Christina (2007). Ency of Shamanism. The Rosen Publishing Group. p. 220.
- Luna, Luis Eduardo (1986). Vegetalismo (Stockholm Studies in Comparative Religion). Almqvist & Wiksell Internat. ISBN 91-22-00819-5.
- Haule, John Ryan (2011). Jung in the 21st Century: Synchronicity and science. Taylor & Francis. pp. 47–48.
- Rozendal, Keith. "Meet Mother Ayahuasca". Retrieved 21 August 2012.