The anti-hyperlipidemic effect of the iodine egg was found to be in the neutral lipid (NL) fraction in its yolk. For the purpose of clarifying the hypolipidemic effect of the iodine-containing NL fraction, the effect of clofibrate (CPIB) was investigated. CPIB was found to lower TC, atherogenic index [(TC-HDL cholesterol)/HDL cholesterol], TG and FFA, but not FC; while NL lowered TC, FC and the atherogenic index, but not TG and FFA. Cholesterol metabolites, probably metabolized in the liver, were examined. Hepatic cholesterol level was increased by NL and CPIB. The ratio of fecal bile acid of the excretion type, lithocholic acid (LCA) to deoxycholic acid (DCA), increased when NL and CPIB were administered, but the hepatic HMG-CoA reductase activity, responsible for the endogenous cholesterol synthesis, was not altered. Thus, the anti-hyperlipidemic mechanism of NL may be the mobilization of peripheral cholesterol to the liver, probably for the disposal by excretion as bile acids.