Cedar leaf oil (Thuja oil) is produced by steamdistillation of fresh leaves and branch ends of the treeThuja occidentalis L. (Cupressaceae). It is a colorless to yellow liquid with a powerful, herbaceous odor, characteristic of thujone. d2525 0.910-0.920; n20D 1.4560-1.4590; α20D ?14 ° to ?10 °; ketone content (calculated as thujone): min. 60 %; solubility: 1 vol in 3 vol of 70% ethanol at 25℃. The oil is produced in the northern states of the United States and in Canada in a quantity of 20–30 t/yr. It is used in perfumery for dry nuances in citrus and woody compositions.