Abstract The essential oil of the leaves of Zanthoxylum ekmanii, collected from the southern Amazon forest, Brazil, was obtained by steam distillation and analyzed by GC and GC/MS. The major components found in the oil were germacrene D (16.0 %) and Î²-caryophyllene (11.5%). Key Word Index: Zanthoxylum ekmanii Rutaceaeessential oil compositiongermacrene DÎ±-caryophyllene