A cholesterol-lowering composition comprising an effective amount of at least one member of LPS whose macrophage activation ED₅₀ is 0.4 - 100 ng/ml of culture solution in terms of its limulus test-positive LPS content observed on a sigmoid curve prepared by determining the ability of the LPS to activate the TNF productivity of macrophage cultured in vitro , and plotting the macrophage activation ability (%) along the axis of ordinate wherein the ability is estimated to be 0 % in the case where it corresponds to the quantity of TNF produced by macrophage with no LPS added thereto, and 100 % is assigned to the macrophage activation ability which provides the maximal and constant quantity of TNF produced by the macrophage and plotting the limulus test-positive LPS content of the LPS along the axis of abscissa on a logarithmic scale, in admixture with a pharmaceutically or veterinarily acceptable carrier, such that when administered to an animal, high cholesterol level of said animal is prevented or cured; and
   a method of treating high cholesterol level of an animal comprising administration to said animal an amount of the above composition effective to prevent or cure the high cholesterol level of said animal.