Objective : The purpose of this study was to investigate the protective effects of Cheongsimondam-tang(COT) on the animal model of depression induced immobilization stress. Method 1) Male rats were used for this experiment. The subject were divided into 4 groups(1. normal 2. saline solution administered during immobilization stress treatment 3. COT of 100mg/kg administered 4. COT of 400mg/kg administered). 2) Immobilization stress was treated for 1 hours on day. During 2 days of immobilization stress treatment, they were executed forced swimming test, passive avoidance test, elevated plus maze test. Corticosterone in blood were measured Results 1) In EPM test, stress group showed significantly increased anxiety, COT groups showed significantly decreased anxiety. 2) In forced swimming test, COT groups did not show significantly decreased immobilization. 3) In passive avoidance test, stress group showed significantly decreased learning execution, COT groups showed significantly increased learning execution. 4) Stress group showed significantly increase in serum level of corticosterone, COT of 400mg/kg group showed significantly decreased serum level of corticosterone. Conclusion : These results suggest that Cheongsimondam-tang(COT) is effective in the treatment of depression.