The purpose of our study is to determine if a relationship exists between the severity of injury in experimental alcoholic liver disease and hepatic levels of leukotriene B4, leukotriene C4 and lipid peroxide. Splague-Dawley rats were fed ethanol (46% of calories) with either safflower oil (SE) or beef oil (BE) (20% of calories) for 12 weeks. Control animals were fed isocaloric amounts of dextrose instead of ethanol with the same diets. The followings were evaluated in each group: hepatic levels of leukotriene B4, C4, lipid peroxide, and collagen-bound hydroxyl-proline, hepatic fatty acid composition, incorporation of 14C-L-proline into hydroxyproline of collagen protein by liver slice. Rats fed SE showed the most abundant accumulation of hepatic hydroxyproline and lipid peroxide. Hepatic leukotriene B4 and C4, hepatic levels of linoleic acid and arachidonic acid were also greater in rat livers from animals fed the SE diet. A strong positive correlation was seen between hepatic levels of leukotrien B4 as well as C4 and lipid peroxide. The hepatic level of lipid peroxide also correlated positively with hepatic levels of linoleic acid and arachidonic acid. Our study shows the importance of leukotriene derived from arachidonic acid cascade in the pathogenesis of experimental alcoholic liver disease.