Fifty percent ethanol extract of Lythrum salicaria Linne root (LSR) was tested in vitro on antioxidant activity, and furthermore was investigated on antioxidative and fibrosis protecting activities in CCL4-induced liver fibrosis rat model. Ratio of hepatic GSH/GSSG (reduced glutathione/oxidized glutathione) as bio-parameter of antioxidant level in CCL4 plus LSR-treated rats for 6 weeks significantly increased from 2.8- to 5.7-fold than that of CCL4-treated rats at p 〈 0.05. Thiobarbituric acid reactive substances (TBARS) contents in CCL4 plus LSR-treated rats ranged from 1.57- to 2.19-fold of normal rats and were lower than those in CCL4 plus silymarin-treated rats (1.78~2.46-fold of normal rats) (p 〈 0.05). Amounts of hydroxyproline of liver tissue showing the content of total collagen, a parameter of fibrosis, in CCL4 plus LSR-administrated rat livers were 4.9~8.8μg/mg (-47~-71%, compared with that in CCL4-treated rat livers (16.6μg/mg tissue), which were significantly lower than those in CCL4 plus silymarin-administrated rats being 8.4~11.7μg/mg (-30~-50%). This collagen reducing effect of liver tissue in CCL4 plus LSR-treated rats was supported by histological observation using microscopy assay. From the results, we conclude that the root of L. salicaria have efficient antioxidant potential and effective antifibrotic activities.