Objective: To study the mechanism of Huangqi Guizhi Wuwu Tang (HGWT) in treating senile pruritus. Method: Totally 84 mice were divided into 7 groups: the normal group

the senile group

the senile pruritus group

the diphenhydramine group (0.65 mg·kg-1)

the low-

middle- and high-dose HGWT groups (3.25

6.5

13 g·kg-1). The senile model was induced in mice by injecting D-galactose at 125 mg·kg-1 subcutaneously on the nape of the neck for continuous 42 days. The senile pruritus model was induced in mice by adding low molecular dextran at 1.25 mg·kg-1 intravenously from the 7th week. The mice were intragastrically administered with distilled water in the normal

the senile and the senile pruritus groups

and the others were intragastrically administered with the corresponding medicines once daily for 7 days. The scratching behavior & its lasting time were observed by a digital video camera. The skin's water content was measured by using drying method. Meanwhile

the sebaceous gland and sweat gland were observed by HE staining

the sum density of aquaporin 3 (AQP3) in skin

lung and liver were observed by immunohistochemistry method. Result: Compared with normal and senile groups

the scratching frequency and lasting time increased

the water content decreased

the number and secretion of sebaceous gland and sweat gland increased

and the AQP3 expression in skin

lung and liver decreased in the senile pruritus group (P<0.05). Compared with the senile pruritus group

the scratching frequency and lasting time decreased

the water content increased

the number and secretion of sebaceous gland and sweat gland decreased

and the AQP3 expressions in skin

lung and liver increased in the diphenhydramine and HGWT groups (P<0.05). Moreover

the results were better in the low- and high-dose HGWT groups (P<0.05). Conclusion: HGWT has a definite therapeutic effect in treating senile pruritus and its mechanism may be related to regulating AQP3 expression.