Abstract The composition of the essential oil obtained from the dried flowering aerial parts of Messerschmidia sibirica L. (Boraginaceae) was analyzed by GC and GC/MS. Twenty-three components have been identified in this the oil. The major constituents of the essential oil were 6,10,14-trimethyl-2-pentadecanone (29.9%), (E,E)-farnesyl acetate (12.3%) and phytol (10.8%)