Increased lipid profile after each meal can disturb the endothelial function. The present study assessed the effects of bread supplemented with oat bran on serum lipids and endothelial dysfunction in patients with hypercholesterolemia. This randomized controlled clinical trial was conducted on 60 patients (age: 20-60 years old) who were receiving statins for hypercholesterolemia. The subjects were selected from hypercholesterolemic participants in outpatient clinics. Individuals with diabetes type one or two, hypothyroidism, renal failure, anemia, cholestasis, pancreatic cancer or malignancy, and secondary dyslipidemia were not included. Patients who used antihypertensive drugs or alcohol, smoked, did vigorous regular exercise, had a history of eating disorders, or had weight changes (losing or gaining more than three kilogram weight during the three months prior to the study) were not included, either. The subjects were randomly allocated to either intervention (consuming at least five daily servings of oat bread with 6 g beta-glucagon) or control (receiving at least five servings of wheat bread). Anthropometric indicators, fasting blood sugar and lipid profiles ere measured at baseline and in the end of intervention. Endothelial function was assessed using flow-mediated dilation.