Abstract: Abstract　Objective: To study the curative effects of arsenic trioxide (AT) combined with a modified fludarabine and cytarabine plus granulocyte regimen (FLAG schedule) on relapsed and refractory acute myeloid leukemia, as well as the therapeutic efficacy of the schedule for leukemia stem cells (LSC). Methods: Ten patients with relapsed acute myeloid leukemia who have been co-treated with AT-FLAG schedule were enrolled in the study to observe the curative effects of the treatment. The proportion of LSC- and P-glycoprotein ( P-gp )-positive cell population in the bone marrow was detected before and after the treatment. Results: After treatment with the combined therapeutic regimen, i.e., the AT-FLAG schedule, severe adverse effects and death were not observed during chemotherapy. The average time of complete continuous remission was 8 months (4-12 months), and complete remission ( CR ) at 3, 6, and 12 months after the treatment was 80%, 60%, and 25%, respectively. Grade IV myelosuppression occurred in all treated patients. The ratio of P-gp+ cells in the bone marrow decreased from ( 23.55% ± 2.75%) before the drug administration to (11.67% ± 3.50%) after the treatment, and the relative amounts of LSC ( CD34+CD38-CD123+ ) before and after the treatment was (4.30% ± 1.30%) and (2.60% ± 0.70%), respectively. Conclusion: The AT-FLAG combined chemotherapy efficiently induced CR of relapsed and refractory acute myeloid leukemia and decreases the LSC and P-gp+ cell content in the bone marrow of patients.