Objective: Evaluation of the antimicrobial and cytotoxic effect of Myrtus communis (M. communis) essential oil as well as chlorohexidine 2%, compared to that of sodium hypochlorite (NaOCl) in mature single-canaled maxillary central incisor teeth. Materials and Methods: 47 mature maxillary central incisor teeth were used in the study. All teeth were autoclaved at a temperature of 121◦C for 30 minutes, two cycles, then Enterococcus faecalis was introduced into the teeth. Samples were kept under humidity at 37 ◦C for three weeks at the incubator. After 3 weeks teeth were divided into 4 groups; Group 1 (control group) 2 teeth. Group 2 (Myrtus communis) 15 teeth. Group 3 (2% CHX) 15 teeth. Group 4 (5.25% NaOCL) 15 teeth. The antibacterial effect was assessed using confocal laser microscopy. The cell viability of all teeth was evaluated using the MTT colorimetric assay. Results: The 5.25% NaOCl group showed the highest percentage of dead cells. The cell viability percentage was highest for Myrtus communis essential oil, while 5.25 % NaOCL had lower viability than the 2% CHX at different concentrations. Conclusions: M.communis essential oil has a more positive impact on cell viability. However, 5.25% NaOCL exhibits the highest antibacterial effect.