The consumption of plant-derived hallucinogenic substances through smoking and snuffing is a longstanding tradition in the south-central Andes. Chemical and archaeobotanical evidence point to the consumption of nicotine and tryptamine alkaloids in Northwestern Argentina and of tryptamine alkaloids in San Pedro de Atacama (SPA), in prehispanic times. In this paper, results are reported of gas chromatographyemass spectrometry (GC/MS) analyses aimed at identifying nicotine and tryptamine alkaloids in the hair of mummies from different cultural periods of SPA. Fifty-six samples were examined. While tryptamines were not found in any of the samples, nicotine was found in 35 samples, assigned to the Late Formative (1 of 1 sample from this period), Late Formative or Middle (1 of 2 samples from either of these periods), Middle (4 of 6 samples from this period) and Late Intermediate periods (8 of 12 samples from this period), or without assignment to period due to lack of contextual information (21 of 35 samples unassigned to a period). These results show a continuous consumption of nicotine from the Late Formative to the Late Intermediate periods of SPA (ca. 100 B.C.e1450 A.D.). No associations were found between presence of nicotine in the hair of mummies and presence of snuffing trays or of other snuffing paraphernalia in the corresponding tomb; furthermore, neither the diversity of the funerary context, measured in terms of the number of types of objects, nor the presence of gemstone necklaces differed between tombs with mummies with or without nicotine in their hair. Overall, these results suggest that consumption of nicotine was performed by members of the society at large, irrespective of their social and wealth status.