Estragole, the major constituent of the essential oil of Croton aff. zehntneri, family Euphorbiaceae, occurs together with minor quantities of camphor, anethole, isoborneol, caryophyllene, y-elemene, safrol, methylisoeugenol, n-heptadecane, and n-eicosane. These compounds are being reported for the first time in the genus Croton. Fifteen predominant volatile constituents of the oil were analyzed by GC-MS and identified. The oil has a typical pleasant odor reminiscent of anise (Pimpinella anisum L.)