Objectives : The purpose of this investigation is to evaluate the effect of Chungpesagan-Tang Extracts on reversible forebrain ischemia in Sprague-Dawley rats. Methods : the volume of cerebral infarction and edema, the pathohistological change of neurons, the number of survived neurons, neurotransmitters through immunohistochemical methods, proteins connected with neurotransmitters through immunohistochemical methods and the pathohistological change of neurons through electro-microscopy were investigated. From these reseach data, the protection of neurons and the activity of brain cells were examined. Results : 1. The infaction volume of the control group was 23.9%, and that of the sample group was 16%. 2. The brain edema volume of the control group increased by 17% compared to the normal group and that of the sample group increased by 10%. 3. The light microscopy revealed that the neurons in the ischemia-induced area and CA1 area of hippocampus were most heavily damaged and that the sample group was less damaged compared with the control group. Most pyramidal neurons died in 7 days when brain ischemia was induced. 4. The number of survived pyramidal neurons in the CA1 area of the hippocampus were studied. The normal group had 93 neurons/mm, survived the control group(after 3 days) had 21/mm, the control group(after 7 days) had 3/mm and the sample group 33/mm. 5. The immunohistochemical methods revealed that: (1) In the control group, the sensitivity of GABA, NOS, DBH were increased, and those of Synapsin, eEF-$1{alpha}$ decreased. NOS and DBH had positive reactions in the control group, but negative in the normal group. (2) In thd sample group, the sensitivity of GABA, NOS, DBH were attenuated, and those of NPY, Synapsin, CaMKII, eEF-$1{alpha}$ increased when compared to the control group. 6. The electro-microscopy revealed that most neurons died by necrosis and some neurons died by apoptosis. Several imflammation cells appeared in the injured area of neurons. The number of neurons in the sample group that died by ischemia decreased. But, the number that died by apoptosis did not significantly change. Conclusions : The data shows that the effect of Chungpesagan-Tang Extracts on reversible forebrain ischemia in Sprague-Dawley rats is significant.