The aim of the present work is to study the seasonal variation of the chemical profile of the essential oil extracted from Elionurushensii and to evaluate its antioxidant activity. Elionurushensii is usually used by local people as théiform drink to relieve aches. The essential oil analyzed by GC-MS presents a different chemical composition in accordance with its origin (aerial part or root). The oil of the aerial part (stems, leaves and flowering tops) is rich in para-menthe dienolisomers (38-49%), the main ones are: the trans-para-mentha 1 (7), 8-dien 2-ol (10.45-20.83%), cis-para-mentha 1 (7), 8-dien-2-ol (10.30-18.81%), trans-para-mentha -2,8-dien-1-ol (5.32 and 16.22%) and cis-para-mentha-2,8-dien-1-ol (3.85-6.39%). The roots are rather rich in aristolone (14-48%) and her chemical structure was confirmed by the analyzes in 1H and 13C NMR. The limonene is also a leading major both of the essential oil of the aerial part (2.21-19.28%) than that of the roots (9.73-30.44%). The antioxidant activity of the oil was evaluated. The essential oil of the aerial part distillates enriched in major compounds present an inhibiting power DPPH greater than that of complete essential oil, but low compared to that of vitamin C.