Abstract: OBJECTIVE To explore the single and combined effects of dictamnine with all-trans retinoic acid (ATRA) on acute myeloid leukemia(AML) cells. METHODS Cell proliferation assay was performed by manual cell counting in Burker chambers; apoptosis was detected by flow cytometry with PI staining; CD11b expression level and cell morphologic changes were used to determine AML cell differentiation. The expression levels of transcription factors CEBPβ and PU.1 were analyzed by western blotting and real-time PCR. RESULTS Both dictamnine single treatment and its combination treatment with ATRA could inhibit AML cell proliferation and induce CD11b expression and morphologic changes, while no obvious apoptosis was observed. Comparing with ATRA or dictamnine single treatment, the mRNA and protein levels of CEBPβ and PU.1 were up-regulated in dictamnine and ATRA cotreated AML cells. Meanwhile, dictamnine alone also had the same effect to induce the expression of CEBPβ and PU.1. CONCLUSION Dictamnine alone can induce AML cell differentiation and also contribute to the ATRA-induced differentiation of AML cells, and the activation of CEBPβ and PU.1 are involved in this process.