Objection : The aim of this study was to investigate anti-ischemic effect of LR1 ${cdot}$ HT8 ${cdot}$ HT9 Reinforcement in Acupuncture. Methods : I designed to investigate whether LR1 ${cdot}$ HT8 ${cdot}$ HT9 Reinforcement in Acupuncture affects cerebral hemodynamics [regional cerebral blood flow(rCBF), pial arterial diameter(PAD), mean arterial blood pressure (MABP) ] in normal and cerebral ischemia rats by MCA occlusion method, and to make manifest whether LR1 ${cdot}$ HT8 ${cdot}$ HT9 Reinforcement in Acupuncture is mediated by cyclooxygenase or guanylate cyclase. The changes of rCBF and MABP were determinated by laser-doppler flowmetry(LDF), and the change of PAD was determinated by video microscope and width analyzer. Results: The results were as follows ; 1. LR1 ${cdot}$ HT8 ${cdot}$ HT9 Reinforcement in Acupuncture was significantly increased rCBF, PAD, but decreased MABP after withdrawing of the needle. This results suggest that LR1 ${cdot}$ HT8 ${cdot}$ HT9 Reinforcement in Acupuncture induced significantly rCBF by dilating PAD. 2. Pretreatment with indomethacin (1mg/kg, i.v.) was significantly inhibited LR1 ${cdot}$ HT8 ${cdot}$ HT9 Reinforcement in Acupuncture induced increase of rCBF and PAD, but increased LR1 ${cdot}$ HT8 ${cdot}$ HT9 Reinforcement in Acupuncture induced decrease of MABP after withdrawing of the needle. 3. Pretreatment with methylene blue(10/${mu}$g/kg, i.v.) was decreased LR1 ${cdot}$ HT8 ${cdot}$ HT9 Reinforcement in Acupuncture induced increase of rCBF and MABP, but accelerated LR1 ${cdot}$ HT8 ${cdot}$ HT9 Reinforcement in Acupuncture induced decrease of PAD. This results suggest that the mechanism of LR1 ${cdot}$ HT8 ${cdot}$ HT9 Reinforcement in Acupuncture is mediated by cyclooxygenase or guanylate cyclase. Conclusion : I suggest that LR1 ${cdot}$ HT8 ${cdot}$ HT9 Reinforcement in Acupuncture has an anti-ischemic effect through the improvement of cerebral hemodynamics, and the mechanism IS mediated by cyclooxygenase.