The generation of reactive oxygen species (ROS) and other reactive nitrogen species (RNS) might be implicated to have a role in the pathogenesis of rheumatoid arthritis. Modulatory agents derived from plants that have properties like scavenging of free radicals clearly have therapeutic potential against these diseases. The present study was aimed to investigate the possible antioxidant potential of Trachyspermum ammi on collagen induced arthritis (CIA) in Wistar rat. Trachyspermum ammi extract (TAE) in a dose of 100 mg kg−1 was orally administered to rat once daily for 21 days after immunization. The estimation of levels of oxidant products and the activities of antioxidant enzymes were carried out in the joints. The induction of arthritis significantly increased the levels of oxidative stress markers like thiobarbituric acid reactive substances and inflammation markers like elastase. The level of non-enzymatic antioxidant, reduced glutathione (GSH) and the activities of enzymatic antioxidants like superoxide dismutase and catalase decreased. The study revealed that the treatment with TAE was effective in bringing significant changes on all the parameters studied as compared with CIA rat. Supplementation with T.ammi reversed the oxidative changes in all the parameters suggesting either termination of cellular infiltration or limiting the generation of oxidants following CIA in rats and might have potential value in the treatment of inflammatory disease.