It is difficult for relapsed and refractory acute myeloid leukemia (AML) patients to achieve complete remission (CR). The CAG regimen [low-dose cytarabine and aclarubicin in combination with granulocyte colony-stimulating factor (G-CSF)] has been used to treat relapsed and refractory AML patients, and showed good therapeutic efficacy. It is unknown, however, whether increasing the dose of aclarubicin in CAG regimen could treat relapsed or refractory AML safely and effectively. We evaluate the efficacy and tolerability of increasing the dose of aclarubicin in CAG regimen, in 37 relapsed or refractory AML patients. All patients were treated with CAG regimen including low-dose cytarabine (10 mg/m(2) every 12 h, days 1-14), aclarubicin (5-7 mg/m(2) every day, days 1-14), and G-CSF (200 μg/m(2) every day, days 1-14) priming. After a single course of therapy, the overall response [CR + partial remission (PR)] rate of all patients was 78.4 % (29/37), in which the CR rate was 62.2 % (23/37). There was no early death. The median overall survival was 6 months (range 2-36 months). Myelosuppression was ubiquitous, but tolerated. No severe non-hematologic toxicity was observed. Thus, increasing the dose of aclarubicin in CAG regimen can be used safely and effectively in the treatment of relapsed or refractory AML.