Although Tianrong acupoint (SI 17) is used for migraine headache, its mechanism of action remains obscure. The effects of Tianrong acupoint therapy on neurogenically-mediated plasma protein extravasation (125I-BSA) in rat dura mater induced by electrical stimulation of the right trigeminal ganglion was studied. When the unilateral trigeminal ganglion was stimulated (5 Hz, 1.2 mA, 5 msec for 5 min), the ratio of stimulated side/unstimulated side (cpm/mg) was 1.6663 +/- 0.0217. The plasma extravasation was blocked by different kinds of treatment in different degrees. The order of the ratio was as follow: Tianrong acupoint therapy (1.0917 +/- 0.0266) and Tianrong electrical needle therapy (1.1281 +/- 0.0227) < Tianrong acupoint injection with normal saline (1.325 +/- 0.0444) < Quchi acupoint (LI 11) injection with prednisolonum (1.5284 +/- 1.1624). The results indicated that Tianrong acupoint therapy could inhibit the neurongenic inflammation on the affected side.