Abstract: Cantharidin of Epicauta ruficeps Illiger was mainly detected in the reproductive glands of males and eggs.Compared with the avarage content of both males and females collected from field,newly-mated males transferred 70% of cantharidin to females,while cantharidin content in newly-mated females increased by 43%.Additionally,it was showed that cantharidin content extracted following hydrolysing this beetle with HCl went up 4 times.This study suggested that this beetle can be used as a supplementary traditional Chinese medicine.