Three new Lycopodium alkaloids, obscurumines C-E (1–3), along with nine known compounds, were isolated from the club moss Lycopodium obscurum L. Structures of the new compounds were determined on the basis of their spectroscopic analysis and the relative configurations of 1 were established by X-ray crystallographic analysis. All the new isolates were tested for the acetylcholinesterase (AChE) inhibitory activity. [Figure not available: see fulltext.]. © 2013, The Author(s).