Korean red ginseng has broad efficacious effects against hypertension, diabetes, nociception, and cancer, and it counteracts weakness. It has been reported that Korean red ginseng is able to normalize blood pressure, improve cholesterol and lower blood glucose levels. We have recently reported that Korean red ginseng extract (KRGE) significantly prevented rat carotid arterial thrombosis in vivo, and inhibited platelet aggregation ex vivo and in vitro in a dose-dependent manner. The purpose of this study was to examine the effects of KRGE on blood circulation in human by measuring ex vivo platelet aggregation, plasma coagulation and serum lipid profiles in healthy volunteers. Subjects were randomly divided into three groups (placebo-group, KRGE-low dose group, KRGE-high dose group). Administration of KRGE to subjects significantly inhibited ADP-induced platelet aggregations both in KRGE-low dose group from $72.79{pm}20.53$ to $62.00{pm}23.06%$ (p=0.0009), and in KRGE-high dose group from $75.14{pm}21.86$ to $64.52{pm}24.72%$ (p=0.0039), respectively. Administration of KRGE to subjects also significantly inhibited collagen-induced platelet aggregations both in KRGE-low dose group from $85.52{pm}12.57$ to $79.62{pm}20.47%$ (p=0.0916), and in KRGE-high dose group from $80.24{pm}18.11$ to $70.31{pm}25.93%$ (p=0.0565), respectively. Whereas, KRGE has no significant effects on coagulation system, such as prothrombin time (PT) and activated partial thromboplastin time (APTT), and serum lipid profiles, such as total cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol and triglyceride. KRGE also has no significant effects on hematological and serum biochemical profiles. These results suggest that KRGE has a potential to improve blood circulation through antiplatelet activity in human, and KRGE intake may be beneficial for the individuals with high risks of thrombotic and cardiovascular diseases.