Objective To observe the activity changes of 8-iso-prostaglandin F2α（ 8-iso-PGF2α） in rats with alcoholic fatty liver disease（ AFLD） and time-effect relationship with Yigan Jiangzhi Formula（ liver-supplementing lipid-lowering formula）. Methods Totally 97 cases of SD rats were randomized into the model group of 22 cases and Chinese medicine group of 75 cases. The AFLD rat models were established with high-fat diet and graded ethanol feeding. The Chinese medicine group was divided into the 3rd week group

6th week group and 9th week group. The rats in the 3rd week group

6th week group and 9th week group were gavaged with 1ml extract of Yigan Jiangzhi Formula（ containing crude drug 1. 33 g /ml） from the 3rd week

6th week and 9th week respectively. The model group was given the same volume of normal saline. The rats were sacrificed in all groups at different time points. The activity of 8-iso-PGF2α and contents of alanine aminotransferase（ ALT）

aspartate aminotransferase（ AST）

triglyceride（ TG） and total cholesterol（ TC） in serum and the activities of malondialdehyde（ MDA） and xanthine oxidase（ XOD） in liver tissue were detected. The pathological changes in liver tissue were observed. Results The activity of 8-iso-PGF2α and the levels of ALT

AST

TG and TC in serum were significantly increased with the modeling time（ P <0.05 or P <0. 01）. Comparing with the 9th week group

the activity of 8-iso-PGF2α and the levels of ALT

AST

MDA and XOD in the 3rd week group（ 3rd to 6th week and 3rd to 12 th week） were significantly decreased（ P <0. 05 or P <0.01）. Under light microscope

the steatosis was gradually increased with the modeling time in the model group. Moderate to severe steatosis accompanied by 3-degree to 4-degree hydropic degeneration could be seen in the model group at the end of the 12 th week. Comparing with the model group

the pathological changes were relieved in all Chinese medicine groups. Comparing with the 3rd week group

the steatosis and hydropic degeneration was significantly decreased in the 9th week group. Conclusion The activity of 8-iso-PGF2α and the degree of liver damage are positively correlated with modeling time. Yigan Jiangzhi Formula has a protective effect on AFLD. The earlier the intervention is given

the better effect is gained. Its mechanism may be relevant to reducing the activity of8-iso-PGF2α

oxidative stress and lipid peroxidation.