['Postprandial hypertriglyceridemia is known to cause endothelial dysfunction and increased oxidative stress. Oral supplements of l-arginine have been found to improve endothelial function. However, the effects of supplements of l-arginine on the influences of postprandial hypertriglyceridemia were not studied before.', 'Forty young healthy men without any risk factors were equally divided into two groups. l-arginine group (age 22+/-1 years, body mass index 23.5+/-1.2 kg/m(2)) received a standard high-fat meal with 15 g oral l-arginine. Control group (age 22+/-1 years, body mass index 23.8+/-0.9 kg/m(2)) received a standard high-fat meal with placebo. A standard high-fat meal consisted of 900 kcal and 50 g of fat. Flow-mediated vasodilation (FMD), von Willebrand factor (vWF), p-Selectin, and glutathione peroxidase (GSH-Px) were measured before and 2 h after the high-fat meal.', 'Serum triglyceride levels were significantly increased 2 h after the high-fat meal in both groups. In the control group, FMD (10.5+/-1.2% vs. 6.8+/-1.4%, p<0.001) and GSH-Px (23.5+/-6.2 vs. 21.9+/-5.0 mug/ml, p=0.029) were significantly decreased after the high-fat meal. P-Selectin (20.0+/-7.7 vs. 25.9+/-10.5 mg/l, p=0.025) and vWF (731.2+/-131.5 vs. 934.9+/-133.8 mU/ml, p<0.001) were significantly increased after the high-fat meal. In the l-arginine group, FMD (10.3+/-1.3 vs. 9.3+/-0.9%, p<0.001) was slightly but significantly decreased after the high-fat meal but not GSH-Px (23.6+/-3.6 vs. 23.0+/-4.8%, p=0.468). P-Selectin (20.1+/-5.9 vs. 25.7+/-10.2 mg/l, p=0.001) and vWF (793.2+/-146.0 vs. 944.4+/-136.8 mU/ml, p<0.001) were significantly increased after the high-fat meal. Degree of FMD attenuation following the high-fat meal was significantly less in the l-arginine group (1.0+/-0.9 vs. 3.8+/-1.5%, p<0.001).'] Do supplements of L-arginine attenuate the effects of high-fat meal on endothelial function and oxidative stress?