Introduction: Sodium hypochlorite (NaOCl) is the chemical agent most frequently used as irrigation solution during endodontic therapy. When extruded to periapical tissue, it is highly toxic. In endodontics, hemolysis caused by NaCOl has been proven using different models, nevertheless, there is little or no evidence of morphological alterations in the cellular membrane of erythrocytes. Objective: To propose an experimental model which might allow to assess morphological alterations suffered by erythrocytes when they are exposed to NaOCl used in the dental practice by means of high resolution scanning electron microscopy (SEM). Materials and methods: In the present study, 20 mL of peripheral blood were obtained and deposited in tubes with EDTA (ethylenediaminetetraacetic acid) anticoagulant. Rinses were conducted with a phosphate buffer solution (Evan’s solution). Several dilutions of the erythrocyte sample were prepared (1:1, 1:2, 1:4, 1:8 and 1:16); 100 μL of each of these dilutions was obtained to be then confronted with 100 μL of dental use 5.25% NaOCl (Viarzoni-T, Medental®); 0.5 μL of these samples were taken to then be deposited in a sample holder made of Zn-Cu alloy which was subjected to a process of Cu ion metallization bath, following the old Spluttering method. Microphotographs were obtained with SEM. Results: Erythrocytes with alteration type anisocytosis and poikilocytosis (stomatocytes, elliptocytes and discocytes) were observed. Some structural characteristics of NaOCl crystals were equally observed. Conclusion: This experimental model allowed assessment of morphological changes experienced by erythrocytes when exposed to 5.25% NaOCl.