The antimicrobial activity of 10 different traditional medicinal herbs extracts against E. coli was determined using paper disc method. Caesalpinia sappan and Rhus javanica, extracts in 5 mg/ml, and Paeonia suffruticosa and Seutellaria baicalensis extracts in 10 mg/ml showed significant antimicrobial activity against E. coli. Minimum inhibitory concentrations of medicinal herbs extracts were in the range of $1.4{sim}8mg/ml;and;1.2{sim}12mg/ml$, for MeOH extracts and EtOH extracts, respectively. In addition, the antimicrobial activity of each solvent fraction was most significant with the EtOAc layer. Optical density at 620nm after 24 hours incubation of E. coli in the presence of 100, 300 or 500 ppm of Caesalpinia sappan extract ranged from 0.02 to 0.1 compared to 0.6 in the absence of Caesalpinia sappan extract, indicating that growth of E. coli was significantly inhibited within 24 hours by the addition of at least 300 ppm of Caesalpinia sappan extract. Optical density at 620 nm after 24 hours incubation of E. coli in the presence of 300 ppm of Rhus javanica extract ranged from 0.02 to 0.2 compared to 0.5 in the absence of Rhus javanica extract, indicating that growth of E. coli was also significantly inhibited within 24 hours by the addition of at least 500 ppm of Rhus javanica extract. In conclusion, these findings suggest that extracts from medicinal herbs may play important roles in antimicrobial activities against E. coli.