Blood serum of patients with documented coronary atherosclerosis induces intracellular cholesterol accumulation in a primary culture of human aortic intimal cells. Serum prepared from blood collected 2–4 h after administration of a tablet containing 300 mg garlic powder (Kwai, Germany) induces a much lower cholesterol accumulation in cultured cells. A tablet with the same amount of garlic but with a prolonged effect (Allikor, Russia) lowers serum atherogenicity for 12–14 h. The direct antiatherogenic effect of garlic powder is confirmed by cell culture experiments with aqueous extracts from garlic powder.