Abstract Re-analysis of the pollen and macrofossil content of residues adhering to sherds of Grooved Ware, excavated from the Balfarg/Balbirnie ceremonial complex (Barclay & Russell-White, 1993), was undertaken to assess the methodology and techniques in analyses on unconventional deposits of this type and also to examine evidence for the use of Hyoscyamus niger (black henbane) in the Neolithic, possibly as a narcotic. Henbane pollen and seeds within the residues had been identified in earlier studies (see Barclay & Russell-White, 1993) and these were related to possible “ritual” activities at the site (Richards, 1993). The re-analysis has highlighted problems with using organic residues from pottery fragments and was unable to find any evidence of henbane or any other poisonous plant in the sampled residues.