This randomized, double-blind, controlled trial evaluated the influence of low fat, low saturated fat food products that contained free tall oil-based phytosterols (TOP) and oat beta-glucan (from whole oats and bran concentrate) on serum lipid concentrations in adults with mild-to-moderate hypercholesterolemia. After a 5-wk National Cholesterol Education Program Step I diet lead-in period, 112 subjects incorporated one of two treatments into their diets for 6 wk: food products (cereal, snack bar and beverage) that provided 1.8 g TOP and 2.8 g beta-glucan/d and contained < or =3.0 g total fat and < or =1.0 g saturated fat (TOP/beta-glucan treatment) or similar control foods. The serum LDL cholesterol response from baseline to the end of study was significantly larger in the TOP/beta-glucan treated group than in the control group, in which there was no change (-3.7 vs. 0.4%; P = 0.013). Likewise, total cholesterol decreased in the TOP/beta-glucan treatment group and did not change significantly in the controls (-2.3 vs. 0.8%; P = 0.043). Serum HDL cholesterol and triglyceride responses did not differ between the groups. The results of this trial suggest that consumption of a group of low fat, TOP and beta-glucan- containing foods is a useful adjunct in the dietary management of hypercholesterolemia.