To study the effect of arsenic trioxide (As2O3) or all-trans retinoic acid (ATRA) on coagulopathy in patients with acute promyelocytic leukemia (APL), and the mechanism of hemorrhage in these patients. Thrombomodulin (TM) or tissue factor (TF) transcription of mRNA of freshly isolated bone marrow blast from APL patients was detected by semi-quantitative RT-PCR. The parameters of coagulation and cell procoagulation activity (PCA) were assessed in plasmic levels. Bleeding symptom was observed during As2O3 or ATRA treatment. TM expression in the APL cell surface was significantly upregulated from (14.31 +/- 1.60) ng/10(7) to (21.61 +/- 6.82) ng/10(7) cells. The levels of P-selectin, soluble fibrin monomer complex (SFMC) and D-dimer (D-D) decreased after ATRA or As2O3 treatment. Abnormal high expression of TF in APL cell was downregulated in patients treated with ATRA or As2O3. The expression level was (14.81 +/- 6.23) ng/L before treatment, but undetected after 20 days of treatment. In addition, the membrane PCA of fresh APL cells was predominantly FVII-dependent after ATRA or As2O3 treatment. Bleeding symptom was ameliorated during As2O3 or ATRA treatment. Bleeding symptom was controlled in patients with APL after As2O3 or ATRA treatment.