To come to a better understanding of the diet-induced cholesterol-ester storage in the gerbil liver, the reactions of the gerbil to 0.2% of cholesterol in the diet during 4 weeks were compared with those of the rat consuming the same diet. The major reason for the increased hepatic cholesterol-ester storage in the cholesterol-fed gerbil is the low cholesterol turnover in this species. This contrasts with the rat. Although faecal acidic steroid excretion can be slightly increased during cholesterol feeding in the gerbil, this increase is not sufficient to compensate for the quantity of dietary cholesterol when administered at the 0.2% level.