ABSTRACT The present study was designed to investigate the antioxidant, antinociceptive and anti-inflammatory activities of the ethanol extract from Ageratum fastigiatum branches. Phytochemical screening and total phenol and flavonoid contents were determined. The antioxidant activity was assessed by 2,2-diphenyl-1-pycrilhydrazin (DPPH) and iron reducing power methods. The antinociceptive effect was evaluated using the acetic acid-induced writhing, formalin, hot plate and tail immersion assays; while the carrageenan-induced paw edema and pleurisy tests were performed to examine the anti-inflammatory activity against acute inflammation. The extract revealed the presence of flavonoids, tannins, coumarins, terpenes, sterols and saponins. Expressive levels of total phenols and flavonoids and a promising antioxidant effect were quantified. At the doses of 50, 100 and 200 mg/kg, the extract inhibited the writhing, reduced both phases of paw licking time and increased the reaction time on the hot plate. In the tail immersion test, the extract (50, 100 and 200 mg/kg) caused a significant inhibition of pain. In these doses, the paw edema, exudate volume and leucocyte mobilization were significantly reduced. These results suggest that A. fastigiatum can be an active source of substances with antioxidant, antinociceptive and anti-inflammatory activities, adding scientific support to the appropriate use in the Brazilian folk medicine.