Objectives : This study aimed to evaluate the anti-stress effects of Guibi-tang and Yisiungyojae-dan on the contents of monoamines in the regional brain of mice immobilized stress. Methods : The experimental animals were immobilized in stress cylinder(height: 15cm, diameter: 3cm) for 15 minutes, and administered of Guibi-tang(6.0mg/10g) and Yishingyojae-dan(9.3mg/10g) water extracts for 7 days before stress. The monoamines contents were measured by HPLC method in various part(frontal cortex, hypothalamus, corpus striatum and hippocampus) of mice brain. Results: 1. In frontal cortex, the contents of norepinephrine were decreased with statistical significantly in Yishingyojae-dan administered group compared to control group. The contents of serotonin were decreased with statistical significance in all of the administered group compared to control group. 2. In hypothalamus, the contents of norepinephrine were decreased with statistical significantly in Yishingyojae-dan administered group compared to control group. The contents of serotonin were decreased with statistical significance in all of the administered group compared to control group. 3. In corpus striatum, the contents of dopamine were decreased with statistical significantly in Yishingyojae-dan administered group compared to control group. The contents of serotonin were decreased with statistical significance in all of the administered group compared to control group. 4. In hippocampus, the contents of serotonin decreased with statistical significantly in Yishingyojae-dan administered group compared to control group. Conclusions: This study shows that Guibitang and Yishingyojae-don are significantly effective on reducing and preventing stress in mice. In addition, Yishingyojae-dan is more clear effective than Guibi-tang on the monoamines change in the mice brain.