Although European conventional maintenance therapy for acute promyelocytic leukemia consisting of all-trans retinoic acid, 6-mercaptopurine, and methotrexate has been adopted in some trials, the adverse events of this therapy have not been described well. We describe adverse events of this therapy in detail and we find that the tolerance of maintenance therapy may depend on the race. Our results indicate that the race and dose intensity should be considered in addition to the number of consolidation courses and PML/RARA mRNA status in configuring the optimal regimen of maintenance therapy, because tolerability may depend much on the races and dose intensity.