Structures of the alkaloids (−)-norfluorocurarine, its racemate (±)-norfluorocurarine from Vinca erecta, and fluorocurarine obtained by N(β)-methylation of (−)-norfluorocurarine were established by x-ray crystal structure analyses. The alkaloid crystallized with two molecules in the asymmetric unit for the first two crystals. The asymmetric unit of (±)-norfluorocurarine crystal consisted of two antipods. The asymmetric unit in the crystal of the last compound consisted of the N(β)-methylated cation and a hydroxide anion. The formation of bimolecular associates through intermolecular N–H…O H-bonds was typical of these crystal- line structures. An associate in the crystal structure of fluorocurarine involved two hydroxide anions.