The present study investigated the antimicrobial properties of medicinal herbs including Scutellariae Radix (SR: dried root of Scutellariae bicalensis Georgi). Among hot-water extracts of medicinal herbs tested in this study, SR extract showed the most potent antimicrobial activity with minimum inhibitory concentration (MIC) of 0.625 mg/mL. In particular, synergistic effects of antimicrobial activity were observed upon combined application of SR and chitooligosaccharide as indicated by MIC of 0.125 mg/mL and FIC (fractional inhibitory concentration) index of 0.45. Thermal stability analysis indicated that the components responsible for antimicrobial activity was stable for 8 months at $45^{circ}C$. Antimicrobial activity was proven to be effective in foods as well as in cosmetics as comparable to that of the chemical preservatives.