AIM: To investigate the alteration of serum free fatty acids in the carbon tetrachloride-induced fatty liver. METHODS: Drug-induced fatty liver rat models were built by injection 40% CCl_4. Serum free fatty acids were analyzed by gas chromatography. RESULTS: In the composition of serun free fatty acids, polyunsaturated fatty acids [oleic acid C18∶1,(28.672?7.332 ?/mg?L~(-1) vs 41.373?2.180 ?/mg?L~(-1)), linoleic acid C18∶2(16.739?0.871 ?/mg?L~(-1) vs 24.959?5.325 ?/mg?L~(-1)), arachidonic acid C20∶4(6.105?2.656 ?/mg?L~(-1) vs 9.802?0.779 ?/mg?L~(-1)),P