Costus speciosus (Koen) J.E. Sm. plant and its extracts are used for treatment of fever, snake bites, jaundice, and as a purgative, astringent and antibacterial agent. In the present study, an attempt has been made to evaluate in vitro antioxidant activity of different extracts of this plant by DPPH radical scavenging activity, total antioxidant capacity, nitric oxide scavenging activity, ion c...