Delphinium elatum L. (bee larkspur) is a Eurasiatic species naturalized under subarctic climatic conditions during cultivation for over 10 years, resistant to unfavorable factors and capable of vegetative and seed regeneration. The alkaloids of its epigeal part at mass flowering were studied: 1 kg air-dry raw material yielded 3 g total alkaloids (0.3% of dry weight), with a crystalline perchlorate identical to nudicauline perchlorate (2.86 g). From the remaining solution, 0.31 g alkaloid mixture was obtained, yielding nudicauline (170 mg, 89% of total alkaloids), 14-deacetylnudicauline (9 mg), 14-acetyldelectinine (base (1), 4 mg, first isolated from this species), and delectinine (21 mg) via chromatography. Base (1) (C26H41NO8, mp 98-102°C) was identified as 14-acetyldelectinine by spectral comparison. Alkaloid content in epigeal parts increased from 0.24% (vegetation start) to 0.3% (mass flowering); hypogeal parts (rhizomes/roots) had higher contents (2.24% at vegetation start, 2.50% at epigeal withering), mostly nudicauline. Cultivated D. elatum differs in alkaloid composition from wild forms: wild plants contain elatine, eldeline, methyllycaconitine, delpheline, delelatine (absent in cultivated), while nudicauline and 14-deacetylnudicauline were only detected in wild seeds.