In this study, APL cells were treated with different concentrations of realgar, and cell viability, apoptosis, morphological changes, ATP levels and cell cycle arrest were measured, and we evaluated, for the first time, the expression of Bcl-2, Bax, Cyt-C and AIF at the mRNA and protein levels following realgar treatment. This evidence concerns the gene BCL2 and acute promyelocytic leukemia.