Ilex guayusa is an Amazonian tree of the holly genus, native to the Ecuadorian Amazon Rainforest. One of three known caffeinated holly trees, the leaves of the guayusa tree are dried and brewed like a tea for their stimulative effects. The leaves contain caffeine and other alkaloids.
The plant is grown primarily in Ecuador in the eastern provinces of Napo and Pastaza, but is found in parts of Peru and Colombia. After harvested, the guayusa leaves are dried which allows flavor to set in.