Objective To observe the effect of herbal plaster at acupoints for the excess syndrome of primary dysmenorrhea and its influence on prostaglandins.Methods The patients with of primary dysmenorrhea excess syndrome were randomized into treatment group（33 cases） and control group（31 cases）.The former was treated by herbal plaster at acupoints while the latter treated by orally taking Tianqi Tongjing Capsule（Radix Notoginseng for Capsule Dysmenorrhea）.Before and after the treatment

the pain scores and the accompanied symptoms were observed;and PGF2α and PGE2 of peripheral blood and renal and hepatic functions were detected.Results After treatment

the pain scores of both groups were significantly decreased（P<0.01）

the therapeutic effect

pain score

and the relief of accompanied symptoms in the treatment group were significantly better than those in the control group（P<0.05 or P<0.01）.In both groups

the content of PGE2α of peripheral blood was increased and the content of PGF2α and the PGF2α/PGE2 were decreased

compared with those before treatment

the difference was significant（P<0.01 or P<0.05）.The PGE2 increase and PGF2α/PGE2 decrease of the treatment group were more than those of the control group（P<0.01 or P<0.05）.Conclusion Herbal plaster at acupoints is effective for the excess syndrome of primary dysmenorrhea

and it is able to regulate the synthesis of prostaglandin.