These plants are lianas. The drug consists of the segments of the lower part of the stem, and is mainly used - or rather misused - by the natives to prepare a narcotic beverage (delirifacient), known variously as "ayahuasca", "caapi", "yagé" (yaje), "yagé del monte ", "oco-yagé", or "caqueta". The drug contains an alkaloid, banisterine (banisterinium) (yageine), C12H12ON2, and is used medicinally in Parkinson's disease (paralysis agitans), on account of its subcortical effect in cases of motor brain-stem symptoms. The above·mentioned narcotic beverage, although it is drunk by many inhabitants of South American countries, is dangerous and can cause paralysis, even death. The stem wood is also used as a fumitory and as a masticatory. According to Beringer (Heidelberg, Germany), the effect of banisterine on some of the symptoms of Parkinson's disease is not a lessening of the trembling, but a partial relief of the stiffness and the restricted motility; he prescribed 0.02 gram of the alkaloid.