One of the most complete scientific studies of ayahuasca yet conducted reported the use by Peruvian Indians of a cultivated Opuntia species, called tchai in Sharanahua, as an ayahuasca admixture, and said to be "very strong." Another cactus, a species of Epiphyllum, known as pokere in Sharanahua and wamapanako in Culina, was likewise added to ayahuasca.(15) A Shipibo informant recently stated that tchai was no longer employed in ayahuasca, the resulting brew becoming too intense.(16) We have no phytochemical data on these cacti, but several species of Opuntia are known to contain low levels of mescaline, (17) and preliminary human bioassays suggest that the B-carboline harmaline might in fact potentiate mescaline - low doses of 60 and 100 mg mescaline hydrochloride, corresponding to 51 and 86 mg base or 0.78 and 1.32 mg/kg respectively, were decidedly psychoactive. The combination of mescaline or mescaline-containing cacti with B-carbolines has been dubbed peyohuasca.(5,18) Anyone else heard of this? Trip reports? That sounds like something that might be interesting to try. Peace, D.