BACKGROUND: Elevation in plasma homocysteine has been widely studied as an independent risk factor for atherosclerosis. And epidemiologic studies have demonstrated that the persons who take the folate and vitamin B6 have lower incidence of atherosclerotic vascular disease and lower plasma homocysteine level. But, not yet the effects of vitamin B6 and folate on the level of plasma homocysteine and brachial artery dilation on healthy subjects was not evaluated. METHODS: We evaluated the effects of 50 mg of vitamin B6 and 1 mg of folate on endothelial function, plasma homocysteine levels to one healthy postmenoausal woman and nineteen men in a randomized, double-blind, placebo-controlled, crossover design. RESULTS: In our study, supplement of vitamin B6 and folate significantly lowered plasma homocysteine level (placebo : folate =6.56 +1.55 micromol/L vs. 5.37 +1.04 micromol/L, p=.001). But, there were no statistically significant increament of flow-mediated dilation (FMD) compared to placebo (placebo : folate =5.12 +3.26% vs. 6.69 +2.60%, p=.070) and there were no significant correlation between the improvement of homocysteine level and increament of flow mediated dilation on healthy subjects. CONCLUSION: Compared to persons with absolute or relative hyper-homocysteinemia, our study did not show such favorable effects in healthy persons. So further studies must to be held to discover the effect of folate and vitamine B6 in healthy persons.