The present invention has for its object to provide a method and a composition for achieving a more efficient recovery of the antioxidant activity of plasma LDL, or even augmentation thereof, which has been depressed by the use of an antihyperlipidemic or cholesterol-lowering drug to thereby insure a potentiated antiarteriosclerotic efficacy. A method for inhibiting arteriosclerosis, which comprises using a combination of a cholesterol-lowering agent and a reduced coenzyme Q10 represented by the following formula (1), and a composition for inhibiting arteriosclerosis containing both a cholesterol-lowering agent and said reduced coenzyme Q10.