A potential mechanism through which the jujube extract might produce a cholesterol-lowering effect was compared with that of tangerine peel extract in vivo. Two extracts were prepared using ethanol. Male rats were fed a high cholesterol (1%, w/w) lab chow with jujube extract (1.2%) or tangerine peel extract (6.3%, w/w) for 3 weeks. Activities of hepatic HMG-CoA reductase (289.6$pm$12.9 and 296.7$pm$11.6 nmole/min/mg vs. 347.9$pm$17.5 nmole/min/mg) and ACAT (554.8$pm$18.2 and 451.7$pm$19.4 nmole/min/mg vs. 602.6$pm$21.4 nmole/min/mg) were significantly lowered by both supplements compared to the control group. These two supplements also substantially reduced the concentrations of plasma cholesterol (103.3$pm$15.9 and 101.6$pm$19.4 mg/dL vs. 141.6$pm$18.1 mg/dL) and triglyceride (61.3$pm$5.5 and 55.5$pm$3.9 mg/dL vs. 96.0$pm$4.2 mg/dL). The inhibition of HMG-CoA reductase resulting from the supplementation of jujube or tangerine extracts could count for the reduction in plasma cholesterol. Accordingly, lipid-lowering action of both supplements appears to be similar in high-cholesterol fed rats.