To explore the impact of formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, hexanal, and pentanal on acellular-nuclear DNA.MethodsDifferent alkyl aldehydes were respectively dissolved in buffer to final concentration of 10 mmol/L. Fragment acellular-nuclear DNA pretreated with the hydroxyl radical was used to detect the interaction capabilities of test substance and DNA, intact acellular-nuclear DNA was used to detect breakage effect of test substance. Six slides with acellular-nuclear DNA, in each group, were immersed in test substances for 60 min, and comet assay was used to measure the changes of the acellular DNA, and 50 acellular-nuclear DNAs were analyzed with Comet A1.0 software in each slide. SPSS 18.0 software was used to compare the difference among groups.ResultsNo fragment of acellular-nuclear DNA treated with formaldehyde migrated to tail, and fragment migration of acellular-nuclear DNA treated with acetaldehyde was more than control. All aldehydes showed no breakage on intact acellular-nuclear DNA.ConclusionFormaldehyde and acetaldehyde could form adducts and/or cross-linked with fragment of acellular-nuclear DNA. The capacity of forming adducts and or cross-linked with fragment of acellular-nuclear DNA decreased with the alkyl number of aldehyde increasing.