o evaluate the efficacy of a newly prepared endodontic irrigant solution, against E. faecalis.Materials and Methods: Sixty human extracted single rooted teeth samples were prepared by using protaper NiTi rotary system. The apical foramen of each sample was sealed by acrylic resin on the apical 3mm. Each root was embedded in silicon impression material block and autoclaved. A ten μl(4X10P5P) of inoculated broth media (nutrient broth) with E. faecalis was injected gently inside the canals of group A,B&C was incubated for 24hours at 37CPoP. Group D was left without inoculation to serve as a control negative. The samples of group A,B and C were disinfected as fallow: Group A was disinfected with MCP solution(mixture of 20% castor detergent and 4% papain). Group B was disinfected with freshly diluted 2.5% NaOCl solution. Group C not treated with any solution control positive. The disinfected solutions were left inside the canal for 5 min then each canal was dried with sterilized paper point, then bacterial samples were taken from the samples of 4 groups using size 40 sterilized file which was inserted to full canal length and rotated 360 degrees in clock wise direction for dentin engagement. The file was put inside the sterilized plastic tube containing 1ml of normal saline then 200 μl was inoculated and spread on Enterococcus agar media and incubated at 37CPoP for 18hours, the numbers of bacterial colonies were counted. Results: Both solutions (MCP and NaOCl) produce complete eradication of E Faecalis within 5 minutes. Conclusion: Castor detergent 20% and papain enzyme 4% (MCP) has ability to completely eradicate Enterococcus Faecalis bacteria from the infected root canal in vitro in 5 min. It's antibacterial action is similar to the action of 2.5 % NaOCl