An attempt was made to test the possible clinical application of the cholesterol-lowering effect of hydrophilic colloids. 10 patients with high mean serum cholesterol levels during a 3-week control period and 9 with normal mean levels were each fed 11.5 g daily of undiluted hydrophilic colloid for 5 weeks. Serum cholesterol decreased significantly in 8 of the 10 (80%) patients with control-period hypercholesterolemia and 6 of the 9 (662/3%) with control-period normal levels. These findings tend to confirm the observation that a simple and commonly used type of medication for chronic constipation, particularly in the elderly, may be a useful adjunct in the managements of hypercholesterolemia.