In the present work, the global yield, composition, and antioxidant activities of the extracts from Achyrocline satureioides obtained by different separation techniques were evaluated. Centrifugation, hydrodistillation, low pressure solvent extraction (LPSE), Soxhlet, supercritical fluid extraction, and ultrasound processes were used. The total phenolic compounds and quercetin present in the extracts were quantified. The antioxidant activity of the extracts was evaluated by the coupled reaction of -carotene/linolenic acid. Higher global yields were obtained by LPSE and Soxhlet. The analysis indicated the presence of flavonoids in all extracts. The antioxidant activities of the extracts were larger than that of the reference substance, -carotene.