Objective: study on efficacy of Vaccinium arctostaphylos (L.) fruit extract in the treatment of hyperlipidemic patients. Study population: hyperlipidemic patients coming to the Diabetes Clinic in Karaj. Sample size: 60 patients. Inclusion criteria: patients aged 20 to 60 years, patients with serum cholesterol level above 240 mg/dl, patients with serum triglyceride level above 240 mg/dl, patients recently diagnosed as hyperlipidemic, literate patients. Exclusion criteria: patients with serum cholesterol or triglyceride levels above 300 mg/dl, patients using other blood lipid lowering agents, patients with cardiac, renal, hepatic, hematological diseases, hypothyroidism, diabetes, tachycardia, vertigo and seizure, patients with a history of gallstones or gall bladder surgery, patients using estrogen, steroid, beta-blocker and thiazide, pregnant women, women planning pregnancy, breast-feeding women. The intervention: Caucasian whortleberry fruit extract is administered to a group of 30 patients at the dose of one 500 mg capsule every 8 hours for 2 months and placebo is administered to another group of 30 patients every 8 hours for 2 months. At the end of the study, the blood lipids levels in the drug group and the placebo group are determined and compared with each other. Primary outcomes: Blood serum level of cholesterol, blood serum level of triglyceride.