Objectives : This experiment was designed to investigate the effect of the BSGE hot water extract on serotonin biosynthesis of depression model. Methods : The cytotoxicity of the BSGE hot water extract was analyzed by MTT assay on P815 cell. The antioxidant activity was measured by DPPH free radical-scavenging activity and SOD activity on P815 cell. The quantity of 5-HT and expression of TPH-1, AAADC and MAOa mRNA was measured by of HPLC profle Analysis on P815 cell. Results : 1. The BSGE hot water extract increased DPPH free radical-scavenging activity and SOD activity on P815 cell. 2. The BSGE hot water extract increased significantly the quantity of 5-HT. 3. The BSGE hot water extract increased the expression of TPH-1 mRNA. Conclusions : This experiment shows that the BSGE hot water extract might be effective for the prevention and treatment of depression. Investigation into the clinical use of the BSGE hot water extract for depression is suggested for future research.