Arctium lappa root extractions were performed using supercritical CO2 (scCO(2)) with methanol as co-solvent. Experiments were performed under the following conditions: 10, 15 and 20 MPa and 313.15, 333.15 and 353.15 K varying the methanol to solids (raw material) mass ratio. The best extraction yield (8.25 wt%) was obtained at 20 MPa, 353.15 K and methanol to solids mass ratio of 1:1. The major compounds found in burdock extracts were diisooctyl phthalate, 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, glycerol and pentadecanal. The extract with higher antioxidant potential was obtained at 15 MPa and 333.15 K (ratio of 4:1), while a higher number of phenolic compounds was found in the extract obtained at 20 MPa and 353.15 K and ratio of 4:1. High-pressure extraction process using scCO(2) with methanol is a promising approaching to obtain burdock root extracts with high biological activity.