A modification of the alkaline filter elution test was used to study damage to liver DNA of NMRI mice following in vivo treatment with various hepatocarcinogens and drugs causing liver enlargement. Liver cell nuclei were prepared and lysed on top of polyvinyl filters. DNA was eluted, and the amounts both remaining on the filter and in the eluate were measured colorimetrically. Dimethylnitrosamine (DMN), diethylnitrosamine (DEN), N-nitrosomorpholine and methyl methanesulfonate (MMS) caused significant enhancement of DNA passage through the filters, whereas N-acetylaminofluorene (AAF), 4-dimethylaminoazobenzene (DAB), phenobarbital, halothane and CCl4 did not. The applicability of this short term test is discussed. © 1979 Elsevier/North-Holland Scientific Publishers Ltd., All rights reserved.