Purpose: These studies were undertaken to evaluate the anti-oxidative and neuroprotective effects of Gamisoyo-san(GMSYS). Materials and Methods: We studied the antioxidant effects of GMSYS by assessing the DPPH free radical and the ABTS radical cation inhibition activities, the total polyphenolic contents(TPC). To evaluate the effects of GMSYS in the human neuroblastoma cells, we measured the cell viabilities in SH-SY5Y cells treated with GMSYS. Then we observed the protective effects of GMSYS against 6-OHDA induced neurotoxicity in SH-SY5Y cells. To confirm the neuroprotective effects of GMSYS in the primary culture of mesencephalic dopaminergic cells, we counted the TH-immunopositive cells and measured the NO and TNF-$alpha$ after the treatment of GMSYS and 6-OHDA. Results: The DPPH free radical and the ABTS radical cation inhibition activities were increased in a dose dependent manner and the IC50 were $133.60{mu}g/m{ell}$ and $106.20{mu}g/m{ell}$, respectively. The TPC was 0.78%. There were no differences between the various concentrations of GMSYS and the control in the cell viability of SH-SY5Y cells. The neuroprotective effects of GMSYS were shown in the co-treatment group at the low concentrations of $25{mu}g/m{ell}$ and the post-treatment group at all concentrations. After the treatment of GMSYS and 6-OHDA in the primary culture of dopaminergic cells, the TH-immunopositive cells were significantly increased in $0.2{mu}g/m{ell}$ of GMSYS than the 6-OHDA group. The NO and TNF-$alpha$ were significantly decreased in $0.2{mu}g/m{ell}$ of GMSYS than the 6-OHDA group. Conclusions: This study shows that GMSYS has the antioxidant and neuroprotective effects, especially in the mesencephalic dopaminergic cells. We suggest that GMSYS could be useful for the treatment of postmenopausal depression related with the degeneration of dopamine neuron.