Abstract : Curcumin, the essential constituent of Curcuma or turmeric, is used widely in many international cuisines. It is known for its pharmacological properties in relatively non-toxic doses. It has been used as probiotics or prebiotics as it has proven medicinal properties since its recognition in 1953. It enhances the overall health of human being by activating or improving the normal micro flora in the colon. This study aimed to investigate the antimicrobial effect of turmeric extract against some species of pathogenic E. coli bacteria hosting surgeries sites and wounds in vitro. 35 samples (swabs) from wounds or surgery sites were collected. The samples were cultured and found bacteria species were isolated and diagnosed. E. coli subtype O157:H7 was isolated form one of the samples and ethanolic Curcumin extract has applied with different concentrations to measure its antimicrobial activity against these subtypes, comparing that to other E. coli subtypes which were collected form stool samples. E. coli O157:H7 showed high resistance to ethanolic curcumin extract with all concentrations. Other subtypes of E. coli where proportionally sensitive to curcumin concentrations. The antimicrobial activity of Turmeric was not strong enough to eradicate E. coli subtype O157:H7. Higher concentrations or other additional factors along with curcumin might be required to enhance its antimicrobial activity