Sinicuichi is very new to most people. Native in Highlands from Mexico to Northern Argentina, Sinicuichi is an interesting and ancient divination plant, but one of the least known in the Western world. The natives believe that sinicuichi has sacred or supernatural qualities, since they hold that it helps them recall events which took place many years earlier as if they had happened yesterday; others assert that they are able, with sinicuichi, to remember pre-natal events.
From The "Golden Guide" we find:
SINICUICHI (Heimia salicifolia) is a poorly understood but fascinating auditory hallucincogen of central Mexico. Its leaves, slightly wilted, are crushed and soaked in water. The resulting juice is put in the sun to ferment into a slightly intoxicating drink that causes giddiness, darkening of the surroundings, shrinkage of the world, and drowsiness or euphoria. Either deafness or auditory hallucinations may result, with voices or sounds distorted and seeming to come from a distance. Partakers claim that unpleasant after- effects are rare, but excessive drinking of the intoxicant can be quite harmful.
Sinicuichi is a name given also to other plants that are important both medically and as intoxicants in various parts of Mexico. Other intoxicating sinicuichis are Erythrina, Rhynchosia, and Piscidia, but Heimia salicifolia commands the greatest respect. With the closely related H. myrtifolia, it has interesting uses in folk medicine. Only in Mexico, however, is the hallucinogenic use important.
Heimia belongs to the loosestrife fomily, Lythroceae, and represents an American genus of three hardly distinguishable species that range in the highlands from southern United States to Argentina. Presence of hallucinogenic principles was unknown in this family, but chemists have recently found six alkaloids in Heimia salicifolia. They belong to the quinolizidine group. One, cryogenine or vertine, appears to be the most active, although the hallucinogenic effects following ingestion of the total plant have not yet been duplicated by any of the alkaloids isolated thus far. This provides us with another example of the often appreciable difference between the effects of drugs taken as natural products and the effects of their purified chemical constituents.
There is more info in the Sinicuichi at Erowid article.
