Wikipedia
Nu-nu is a psychoactive drug prepared and administered by Matsés people of the Amazon to prepare the men for a successful hunt.
To prepare the snuff, the powdered roasted leaves of mapacho (N. rustica tobacco) are mixed with alkaline ashes of the inner bark of the mocambo tree (wild cacao, Theobroma bicolor, which, in the proper amount, improves the absorption of the drug while lessening the nasal irritation. The leaves and alkalizing ashes are ground into a very fine powder and mixed.
A Matsés man administers the prepared snuff by blowing the powder through a bamboo tube into the recipient's nostril. Under the effects of the drug, the recipient has visions of the location of game (such as peccary) in the surrounding rainforest. A Matsés man may receive as many as four doses of nu-nu in each nostril.
Alternatively, nu-nu is also taken sublingually, to much milder effect.