Objectives : The purpose of this study was to investigate the protective effects of Magnolia Officinalis extracts on the animal model of depression induced by immobilization stress. Methods : The subjects were divided into 4 groups : normal, saline solution-administered during immobilization stress, 200 mg/kg of magnolia extracts-administered (magnolia extract 200), and 400 mg/kg of magnolia extracts- administered (magnolia extract 400). During 2 days of immobilization stress treatment, they underwent forced swimming test (FST) and tail suspension test (TST). The number of serotonin (5-HT) immunostained nuclei in the dorsal raphe nucleus regions was measured by immunohistochemistry. Superoxide dismutase (SOD) and glutathione peroxidase (GPX) in blood were measured. Results : In FST, magnolia-administered groups showed significantly decreased immobilization. In TST, the magnolia extract 400 group showed decreased immobilization. The stress group showed significantly decreased number of 5-HT immunostained nuclei in the dorsal raphe nucleus regions, while magnolia extract 400 group showed increased number of 5-HT immunostained nuclei. Stress group showed decrease in serum level of SOD and GPX, while the magnolia extract 200 group showed increase in serum level of SOD and GPX. Conclusions : These results suggest potent effectiveness of magnolia extracts in the treatment of depression.