Five new C18-diterpenoid alkaloids, anthriscifoltines C-G (1–5), along with four known diterpenoid alkaloids anthriscifolcines C-F (6–9), were isolated from the extract of Delphinium anthriscifolium var. majus. Their structures were elucidated by extensive spectroscopic analyses (including 1D-, 2D-NMR, and HR-ESI-MS). Compounds 1–5 were also evaluated for their cytotoxic activity against MCF-7, HepG2, and H460 human cancer cell lines. © 2017 Informa UK Limited, trading as Taylor & Francis Group.