Abstract: Objective: To investigate the pathological change and expression of malondialdehyde( MDA),superoxide dismutase( SOD),tumor necrosis factor-( TNF-) and interleukin-1( IL-1) in gastrointestinal tissue of rats with acute paraquat( PQ) poisoning. Methods: Forty SD rats were randomly divided into control group and poisoned group( 10 rats and 30 rats,respectively). The control group and poisoned group were disposably perfused with normal saline and 180 mg / kg of the diluent of normal saline and PQ, respectively. The gastrointestinal tissue of control group( 10 rats) and 10 rats of poisoned group at 6,24 and 72 h after treatment were harvested. Gastrointestinal gross morphology was observed. The pathological change,the expression of MDA,SOD,TNF- and IL-1 in gastrointestinal tissue were detected by immunohistochemistry( IHC),and the expression of TNF- and IL-1 in gastrointestinal tissue were detected by ELISA. Results: There were obviously pathological injury in gastrointestinal tissue of rats with acute PQ poisoning. The expressions of MDA,TNF- and IL-1 in poisoned group were significantly higher than those in control group( P 0. 01),the expression of SOD in poisoned group was significantly lower than that in control group( P 0. 01). Conclusions: There are obviously pathological injury in gastrointestinal tissue of rats with acute PQ poisoning. The inflammatory response and oxygen free radicals may play an important role in gastrointestinal injury of poisoned rats.