To develop anticariogenic agents, Scutellariae Radix was tested for its antibacterial activity against Streptococcus mutans OMZ176 which is known as a strong cariogenic bacterium. The antibacterial activity was evaluated with disk plate method and minimal inhibitory concentration (MIC). The ethyl acetate fraction showed significant activity. By means of activity-guided fractionation, baicalein and ganhuangenin were isolated as the active principles. The MICs of these compounds were $100{mu}g/ml$ and $200{mu}g/ml$, respectively.