It generally has been assumed that the Peruvian substance known as Vilca is, or was, a snuff made from a Piptadenia in the family Leguminosae (Safford, 1916; and later authors). However, there is evidence in the literature and in unpublished materials that Vika may involve other plants as well, and that it may have been used in forms different from snuff. I would like to examine this evidence with a view to opening new areas in the search for psycho-active drugs. The discussion which follows is based in part on research in the ethnobotany of the strictly New 'Vorld genus Anadenanthera, which formerly was considered as section Niopa of the genus Piptadenia and is known commonly as the source of some hallucinogenic snuffs. The genus Anadenanthera contains two very similar species which have not been shown to differ significantly with respect to their psycho-activity, and which may have been used interchangeably. One species is Anadenanthera colubrina, found in southern Peru, Bolivia, northern Argentina, Paraguay and southern Brazil. The other species is A. peregrina, ranging from southeastern Brazil to the Greater Antilles. (von Reis, 1961; von Reis Altschul, 1964). This paper has posed many more questions than it has attempted to answer, but it has been instrumental in pointing out some unusual approaches to a better knowledge of Vilca, which could serve as a model for studies on other little known so-called narcotics. The facts gathered here suggest that a number of hitherto unsuspected species should be analyzed for psychoactivity, and that the drug plants used 'by man in the New World may prove to constitute a richer and more elaborate complex than we yet have been led to believe. The early writings deserve to be read again, and herbarium information should be sought more assiduously.