The piperidine alkaloid content of the spruces Picea abies, P. glauca, P. pungens and P. sitchensis, and the pines Pinus edulis, P. flexilis, P. jeffreyi, P. nigra, P. pinea, P. ponderosa and P. sylvestris was assessed by isolation and GCMS. The spruce species contained a variety of cis- and trans-2, 6-disubstituted piperidine alkaloids, while the pines contained only cis-disubstituted piperidines. In some species the alkaloid patterns of individual plant parts were determined. Preliminary bioactivity of some of the piperidines is reviewed. © 1994.