The essential oil yield from the aerial parts of A. campestris was 0.2% (mL/g dried plant). The oil was analyzed using GC and GUMS and 38 compounds were identified. The principal components were sesquiterpene alcohols: spathulenol (9.2%) and 4-hydroxy-9-epi-beta-caryophllene (3.0%); and monoterpene hydrocarbons: beta-pinene (9.1%), alpha-pinene (3.4%), limonene (2.5%) and germacrene D (3.3%).