As indicated by Schultes and Holmstedt (1968), the sources of narcotic snuffs used by South American natives have been treated vaguely and often were based on uncertain botanical identifications. As these authors also point out, it had long been the assumption that such snuffs were produced wholly either from tobacco or from Anadenanthera peregrina (more commonly known as Piptadenia peregrina). Thanks to the intensive research on this subject, principally by Schultes and Holmstedt (1968), it is now known that other important plant sources are used, such as various species of Virola (V. theiodora, V. elongata, V. calophylla, and V. calophylloidea), Elizabetha princeps, and Justicia pectoralis var. stenophyUa. Moreover, the combination of Virola, Elizabetha, and Justicia is used by some South American natives to the exclusion of Anadenanthera peregrina. During October of 1971 the present authors were based at the Maturac~ Mission in Brazil, participating in a botanical exploration of the summit of Cerro de la Neblina (Serra do Neblina) with helicopter facilities provided by the Frontier Commission of Venezuela and Brazil through the good graces of Mr. Georges Pantchenko. Our observations further corroborate the botanical identifications and data published by Schultes and Holmstedt (1968) concerning the narcotic drug plants used by the Indians of the Maturac~ area and emphasizes of the importance of species other than Anadenanthera peregrina in the production of narcotic snuffs.