To explore the mechanism of alcohol extract of Melia toosendan in inhibiting cell proliferation in acute lymphoblastic leukemia(ALL).Methods:An CCRF-CEM cell line and 12 SD female rats of SPF grade aging six weeks were selected.The effect of M.toosendan alcohol extract on the inhibition and apoptosis of CCRF-CEM cells was observed after the treatment with M.toosendan alcohol extracts of different concentrations for 24 h，48 h，and 72 h.Results:M.toosendan alcohol extracts of different concentrations(16，80，and 400 mg/L) for treatment for different time periods showed an obvious effect on the inhibition of the proliferation of CCRF-CEM cells.Compared with the control group at the same time point，the absorbance values of M.toosendan alcohol extracts of different concentrations were different，and the absorbance values gradually decreased with the increase in quality(P<0.05).Compared with the control group，there was no significant difference in the absorbance of 16，80，and 400 mg/L alcohol extracts of M.toosendan on peripheral blood lymphocytes at the same time(P>0.05)，suggesting that alcohol extracts of different mass concentrations had no obvious toxic effect on peripheral blood lymphocytes.Compared with the control group at the same time point，the expression of B-cell lymphoma-2(Bcl-2)，Bcl-2-associated X(Bax)，and P53 genes in the alcohol extract of M.toosendan groups of different concentrations was different(P<0.05).The gene expression of Bax increased with the increase in mass concentrations，while the Bcl-2 expression level decreased with the increase in mass concentration.The P53 gene expression level in the 400 mg/L M.toosendan alcohol extract group peaked at 24 h，while the gene expression showed an upward trend after the treatment of ALL cells for 48 h(P<0.05).Conclusion:The alcohol extract of M.toosendan can inhibit the proliferation of CCRF-CEM cells through mitochondria in a concentration-and time-dependent manner.