〔Abstract〕 Objective To explore the causal relationship between the abundance of intestinal flora(IF) and the risk of developing acute myeloid leukemia(AML) using two-sample bidirectional Mendelian randomization(MR) methods. Methods The MiBioGen Consortium and FinnGen databases were utilized for the IF abundance and AML genome-wide association datasets, respectively. The primary analysis method entailed variance inverse weighting, supplemented by weighted median test, while heterogeneity was assessed using Cochran′sQtest. Additionally, MR-PRESSO was employed to identify any outliers, while MR-Egger intercept was utilized to evaluate horizontal pleotropy. Results Higher abundance of genetically determinedDialister(P=0.034,OR=4.373,95%CI:1.329-14.392),Veillonaceae(P=0.009,OR=2.029,95%CI:1.839-3.866), andLachnospiraceae UCG008(P=0.034,OR=3.827,95%CI:1.107-13.228) were found to be linked to an increased risk of AML. In contrast,Ruminococcaceae(P=0.042,OR=0.176, 95%CI:0.033-0.939) andPeptococcaceae(P=0.025,OR=0.168, 95%CI:0.035-0.803) were associated with a reduced risk of this disease. Conclusion Higher levels of theDialister, theVeillonellaceae, and theLachnospiraceae UCG008are risk factors for AML, while the familiesRuminococcaceaeandPeptococcaceaeare identified as protective factors against AML.