The National Heart, Lung, and Blood Institute (NHLBI) has recommended intensive dietary treatment as first-line therapy for patients with high cholesterol levels. The NHLBI has also encouraged research into the effectiveness and safety of alternative diets and further study of human behavior as it relates to adherence to diets. Based on these recommendations and previous studies suggesting a hypocholesterolemic effect of oat bran dietary supplementation, 16 family practice outpatients with elevated cholesterol levels were enrolled in a 12 week study designed to assess the practicality and effectiveness of adding four oat bran muffins per day to the diet. Subjects were randomized into immediate intervention and delayed intervention groups. The combined group had a significant decrease in total cholesterol of 7.9 percent (p less than .03) and in LDL-cholesterol of 10.1 percent (p less than .03) but there was no significant difference with respect to lipid changes between the immediate group and the delay group when the delay group was serving as a control for the immediate group. The results taken in conjunction with evidence in the literature indicate that the simple addition of oat bran muffins to the diet of certain family practice outpatients is well tolerated and probably effective in lowering serum total and low density lipoprotein cholesterol.