A process for preparing a practical cholesterol-lowering compound by converting the cholesterol contained in a food or feed to coprostanol having very low intestinal absorption by utilizing an enzymatic action. The content of cholesterol in cholesterol-containing materials such as meat, eggs, milk, fishery products, and cooked and processed foods containing these products, or feed for animals, poultry, fish culture and the like is lowered by treating these materials with three enzymes, i.e., a cholesterol dehydrogenase having an optimal pH value in a neutral pH range and a 4-cholesten-3-one dehydrogenase and a coprostan-3-one dehydrogenase both having an optimal pH value in a weakly acidic range, or cells containing these enzymes to convert cholesterol to coprostanol.