The effect of Baimai Paste on microcirculation was explored through counts of blood vessels and mastocytes after the Paste was applied to some acupuncture points of nude mice.Methods:15 BALB/C-nu adult nude mice were divided to the treatment group and the no-treatment group， and attended to accordingly. On Day 7， skins of treated areas (around the 4th thoracic vertebra) on the back， of untreated areas of the same subject， and skins of corresponding areas from no-treatment mice were collected， sectioned， stained and observed.Results:an increase of expanding blood vessels and mastocytes were seen in the dermis of the treated areas compared with less increase of those in the no-treatment areas or subjects. Statistics analysis showed very significant differences in increase of blood cells and mastocytes when comparison were made between the treated skin areas and no-treatment areas of the same subject， or the control group (P<0.01).Conclusion:Baimai Paste can significantly expand blood vessels and stimulate aggregation of mastocytes.