Calea zacatechichi is a shrub of the sunlower family ranging from central Mexico to Costa Rica. The specific name is derived from the Aztec word for bitter grass which it is also sometimes called.

This plant has known long use in folk medicine, especially in the treatment of fevers and as an astringent in cases of diarrhoea.
The Chontal Indians of Oaxaca use the plant to induce hallucinations.  Crushed dried leaves are steeped in boiling water and the resulting tea is drunk slowly.

The Indian user then lies down down in a quite place and smokes a cigarette made from the dried leaves of the same plant. The Indian knows that he has taken a large enough dose when a sense of respose and drowsyness is experienced and when he hears his own heart and pulse beats.