Here is a file from my board (Altered Consciousness) about practical uses of Yage.

"The vine is prepared in an incredibly diverse range of technique. Alone, the vine bark is scraped from the freshly harvested stem. The bark is boiled for several hours. The stripped vine is then macerated and boiled for several hours in a seperate container. These are then combined and taken in various amounts....depending of the original length of the vine. All this is further complicated (and McKenna reiterates this as well) by the various admixtures of other plants into the brew of the plain caapi.

Most of these are rich in the DMT family of alkaloids, which are not normally active orally, but since Harmine/Harmaline is a monoamine-oxidase inhibitor, it renders these quite potent when ingested orally. Some of the leaves of the plant B. rusbyana are often added, as are Virola theiodora, both of which are RICH in DMT and 5-MEO-DMT."

I will quote the article I refered to earlier MeKenna wrote, in closing:

"After spending seven weeks deep in the Amazonian rain forest, it became clear that the quality and efficacy of the various brews we imbibed depends entirely on the knowledge, personality and care used by the person preparing it. B. caapi is completely different by itself; the quality of the effect is RADICALLY altered by the various admixtures of the other DMT containing plants!"