The aim of this study was to evaluate the cytotoxic effect of the azo dye corafix on Allium cepa L. The dye was evaluated at the doses of 10, 100 and 1000μg/l at the exposure times of 24, 48 and 72. A total of 5000 cells was analyzed for each dose cellular aberration study. The mitotic index was calculated, and statistical analysis was performed using the Chi-squared test (p < 0.05). The results depict that under the dye at the evaluated doses and exposure times were mito-depressive and clastogenic. Cytotoxicity studies should be conducted for further evaluation of the effect of the dye in a natural system