This study examined the effects of Lactobacillus plantarum(LP) cultured in Platycodi Radix decoction(LPPR) on the expressions of NO and TNF-${alpha}$ in mouse macrophage RAW264.7 cell line. Cells were stimulated with LP or LPPR (0.1, 1, and 10 bacteria/cell) in all assays. More NO was induced in LPPR than LPM at 0.1 and 1 of a LP: cell ratio. The iNOS mRNA expression was also enhanced in LPPR stimulated cells. TNF-${alpha}$ was increased in LPPR stimulated cells at the protein and mRNA level compared with LPM. In conclusion, LP fermented in Platycodi Radix decoction induced stronger activity in NO and TNF in mouse macrophages than LPM. These results suggest that fermentation by Platycodi Radix can be useful in enhancing the immunostimulatory activity of LP.