Sand rats develop obesity, insulin-resistance, hyperlipidemia and prediabetes, when given a standard laboratory chow diet. We have used this model to demonstrate the beneficial action of olea europea var. oleaster leaves to regulate unbalanced metabolism. 32 sand rats fed on hypercaloric diet during 7 months, were divided into 3 groups: controls (n=10), treated by plant (n=13) and treated by simvastatin (Zoco); hypocholesterolemic drug. The plant decoction prepared at 10% was given orally at the rate of 1.5 ml/100g during 3 months. Results show that the plant presents a hypocholesterolemic effect (42%) related to decreases in LDL and VLDL cholesterol. In addition, hypoglycemic (16%) and antihyperglycemic (40%) effects were observed accompanied by a 27% decrease in insulin. Chronic treatment with Zocor reduced total cholesterol (32%), LDL and VLDL cholesterol. Both of treatments produced no significantly reduction in plasma levels of triglycerides and HDL cholesterol. No noxions effect of this plant have been observed in usual doses.