The amount and type of dietary fat is thought to be important in the pathogenesis of alcoholic liver disease (ALD). We investigated the role of different dietary fats in our rat model for ALD. Liver pathology was evaluated in rats fed ethanol and lard or tallow or corn oil over a period of 2 to 6 months. All experimental animals were pair-fed the same diet as controls except that glucose was isocalorically replaced by ethanol. Rats fed tallow and ethanol developed none of the features of ALD, those fed lard and ethanol developed minimal to moderate disease, rats fed corn oil and ethanol developed the most severe pathology. The degree of histopathological abnormality correlated with the linoleic acid content of fat in the diet (tallow 0.7%, lard 2.5%, corn oil 56.6%). We postulate that linoleic acid facilitates development of ALD and provides an explanation for our previous epidemiological observations.