A new alkaloid buxaline-C has been isolated from Buxus sempervirens cultivated in Tashkent. The results of a comparison of the physicochemical properties of the products of the hydrolysis of buxaline-C and those of cycloprotobuxine C have enabled the structure and configuration of buxaline-C to be determined as 3β-acetylmethylamino-20β-dimethylamino-4,4,14α-trimethyl-9β,19-cyclo-5α-pregnane. © 1976 Plenum Publishing Corporation.