Part one of the paper discusses ethnobot~i~~, chemical and general ph~ma~ological aspects of intoxicating snuff rituals in the western hemis- phere. Four categories of ritual snuff ingredients arise from this multidisci- plinary approach : (1) It is well established that the plant contains one or more psychoactive principles and the Indian use of the plant as a ritual snuff ingredient is con- firmed or quite probable: Anu~enanthe~a, Erythroxylu~, ~icot~nu, Virola; (2) It is well established that the plant contains one or more psychoactive principles, but the Indian use of the plant as a ritual snuff ingredient is not well recorded or even unlikely: Banisteriopsis, Cannabis, Datura, Ilex guay- usa; (3) The Indian use of the plant as a ritual snuff ingredient is confirmed or quite probable, but it is not well established that the plant contains one or more psychoactive principles: Justicia pectoralis, Pagamea ~acrophyl~u, Tanaecium not turnum; (4) The Indian use of the plant as a ritual snuff ingredient is not well recorded, and it is not well established that the plant contains one or more psychoactive principles: Acorus ~aiu~us, Capsicum, ~ac~uira sclerophylla, Piper inter~tu~. Part two of the paper discusses the nasal pharmacokinetics and efficacy of possible ritual snuff constituents. The literature yields convincing clinical evidence that atropine, cocaine, nicotine and scopolamine are effective following nasal application, but experimental confirmation of the efficacy of nasal tryptamine alkaloids is still awaited. In self-experiments, 6.4 mg/kg of Caffeine produced substantial plasma levels via the nasal route, but 0.5 mg/kg of harmine did not produce measurable plasma levels, when taken as a nasal powder. Without additional experiments, it is difficult to give a definite explanation for this negative result.