Objective: To study the effects and mechanism of the extract of Ginseng Radix et Rhizoma on hair growth of C57BL/6J mice. Method: This experiment had 5 groups: positive control group (zhangguang 101)

blank control group

high dose group (2 g·mL-1)

medium dose group (1 g·mL-1)

low dose group (0.5 g·mL-1). The skin color and histological examination of hairless mice were investigated to study the effects of promoting hair growth. The skin temperature at different time was measured with infrared radiation thermometers and platelet aggregation rate in vitro was surveyed with nephelometry and chromogenic substrate to preliminarily study the mechanism. Result: All dose groups could induce the hair growth of C57BL/6J mice in a dose-dependent manner from resting stage to growing period

but had no effect on final length of the hair. The differences were significant (P<0.01) between the therapeutic groups and the controls

but no significant between high dose group and positive control group. Histologic examination showed that the extract of Radix Ginseng could produce melanin and induce C57BL/6 mice hair follicle to enter from telogen into anagen. Twenty and sixty minutes after administration

all dose groups can significantly improve the temperature of mice (P<0.01)

however

one hundred and twenty minutes later

the temperature recovered to initial time. The blood platelet aggregation induced by platelet activating factor (PAF) at five minutes could significantly and concentration-dependently be inhibited by all dose groups

the platelet aggregation rates of different doses were 49.41%

27.80%

18.39%

repevtively

and the differences were significant between the therapeutic groups and the blank control group (P<0.01)

but there were no significant differences between the Ginseng Radix et Rhizoma groups and the positive control group. The platelet aggregation activity was partially related to antithrombin and the thrombin inhibition rates of different doses were (20.24±2.72)%

(15.42±1.03)%

(8.61±0.80)%

respectively. The differences were significant between the therapeutic groups and the blank control group (P<0.01). Conclusion: The mechanism of the extract of Ginseng Radix et Rhizoma on hair growth of C57BL/6J could be connected with expending skin capillary and improving local microcirculatory perfusion.