The aim of this research was to investigate the antibacterial activity of Parasenecio pseudotaimingasa, a perennial plant belonging to the Asteraceae, tribe Senecioneae. The methanol extract, n-hexane fraction, and n-butanol fraction of P. pseudotaimingasa leaves all exhibited antibacterial activities against Escherichia coli and Staphylococcus aureus, forming inhibition zones greater than 11 mm in discs. Among them, the n-hexane fraction showed the highest antibacterial activity against E. coli and S. aureus, with an inhibition zone greater than 14 mm. Open-column chromatography was used to isolate the phytochemical constituents from the n-hexane fraction; spectroscopic analysis elucidated their structures as ${eta}$-sitosterol and daucosterol. Further testing of ${eta}$-sitosterol and daucosterol also revealed the antibacterial effects against both E. coli and S. aureus, suggesting their potential as antibacterial agents.