The botanical and phytochemical evidence shows that the Banisteriopsis spp. stem material contains both harmine and harmaline (but no DMT) as previously reported and serves as the source for these psychotomimetic principles in the beverage. The two Psychotria spp. were found to be different, both by classic microscopic methods, and on the basis of the presence of DMT in "nai kawa" and the total absence of alkaloids in "matsi kawa." This does not, however, preclude the possibility that "matsi kawa" contributes some pharmacological activity since attempts to simulate the cardio vascular effects of the beverage ("nixi pae") , using the alkaloids found (i.e., DMT, harmine, and harmaline), were not successful. The concentrations of DMT in the "nai kawa" ranged from 0.165% to 0.222% in the leaf and from 0.066% to 0.108% in the stem. The beverage was found to contain 0.023% (W/V) to 0.015% (W/V) of DMT, 0.007% (W/V) of harmine, and 0.01% (W/V) of harmaline. An interesting and unusual side benefit from this study was the demonstration that Psychotria psychotriaefolia (later correctly identified as Psychotria viridis) also contained DMT as and possibly dehydro DMT. It also is used "nai kawa" by the Kofan and has been reported on by Pinkley (5) . As far as we have been able to determine by a carefull search of the literature, this is the first report of the occurrence of N,N-dimethyltryptamine in the Rubiaceae family. This interesting find may have important chemotaxonomic significance which is not now apparent.