This research was carried out to determine a potential role of leukotrienes in the acute hepatotoxicity induced by CCl4 in rats. An inhibitor of leukotrienes biosynthesis, diethylcarbamazine (DEC, 25 and 50 mg.kg-1 ip) exerted hepatoprotective effects, decreasing the activity of alanine aminotransferase in serum and the concentration of liver triglycerides. DEC reduced histological damage of liver evidenced by electron microscopy. The hepatoprotective effects of DEC were dose-dependent. The results favor the role of leukotrienes in CCl4 hepatotoxicity.