Effects of glycyrrhizin, an active principle of liquorice, on cholesterol metabolism, and its correlation with cortisone action were investigated using adrenalectomized rats.(1) Incorporation of acetate-1-¹⁴C and mevalonate-5-³H into cholesterol of liver slices was greatly stimulated by glycyrrhizin pretreatment, i. e., 1-10mg esp. 1mg per 100g body weight per day intramuscularly for 5 days. Combined administration of glycyrrhizin with cortisone even weakened the stimulatory action of glycyrrhizin, although cortisone itself had a stimulatory action on cholesterogenesis.(2) Direct addition of glycyrrhizin in vitro to the incubation media containing liver slices of normal rats also increased cholesterogenesis at the concentration of 10^-5-10^-3M.(3) Excretion of intravenously injected cholesterol-4-¹⁴C into bile of bile duct-cannulated rats was much accelerated by glycyrrhizin pretreatment, 2mg per 100g body weight per day intramuscularly for 5 days. Rates of increase of radioactivities excreted into bile by glycyrrhizin pretreatment were 4.5 times, taurocholic acid; 2.8 times, taurochenodeoxycholic acid; 2.7 times, cholesterol; and 3.7 times, total ¹⁴C, respectively.(4) Fecal excretion of intraperitoneally injected cholesterol-4-¹⁴C was also stimulated by glycyrrhizin pretreatment. Total ¹⁴C and total bile acids-14C were increased up to about 2 times, while non-saponifiable materials-¹⁴C and 3β-OH-sterols-¹⁴C remained within 1.5 times.(5) Elimination of intravenously injected cholesterol-4-¹⁴C from plasma was accelerated by glycyrrhizin injection.(6) Glycyrrhizin treatment reduced plasma cholesterol and triglycerides levels of cholesterol diet fed rats.