Rhabdosciadium aucheri (Apiaceae) is a perennial herbaceous species, which is endemic to W, S and C Iran. In the present study aqueous, ethanolic and methanolic extracts were obtained from aerial parts of the specimens collected from Hamadan province, using both Maceration and Soxhlet methods. Due to the direct relationship between total phenolic and flavonoid contents and the plant antioxidant activity, the aim of the present investigation was the comparative study of total amount of each parameter extracted by aqueous and hydroalcoholic solvents. The results demonstrated that, the highest amount of phenolic and flavonoid compounds extracted by ethanolic solvents using Maceration technique were 37.28 ± 1.03 mg GAE/gr GW and 22.68 ± 0.63 mg QE/gr DW respectively. These results were significant at p < 0.05. Moreover, 72.17 ± 17.10 % was the highest free radical inhibition percentage for methanolic extracts. However, the differences were not considered as significant. The results also showed that using hydroalcoholic solvents are more powerful compared to aqueous solvents in the extraction of phenolic and flavonoid contents and consequently their antioxidant activity. Manuscript profile