The essential oil of Bupleurum fruticescens was investigated qualitatively and quantitatively by GC and GC-MS analyses. The anti-inflammatory activity of the whole essential oil and its major components was also investigated in the rat hindpaw edema model induced by carrageenin or by PGE1. The anti-inflammatory activity shown by the essential oil can be attributed to the two major components, alpha-pinene and beta-caryophyllene. In order to know the role of the adrenal glands in the anti-inflammatory activity exerted by the two major components of the essential oil, they were studied against the carrageenin-induced hindpaw edema in adrenolectomized rats. It is concluded that alpha-pinene needs the integrity of the adrenal glands to exert its anti-inflammatory activity, as opposed to beta-caryophyllene which was also active in adrenolectomized animals.