Muntjac cells were cultured at 5X10(5) cells/10 cm Petri dish for 24 h prior to addition of fatty acids (50 mu M) which were delivered to the cells complexed with 2% bovine serum albumin (fatty acid-free) and incubated for a further 24 h, Parallel dishes were processed for lipid extraction and GC analysis. This analysis showed highly significant (P < 0.01) uptake by the cells of each fatty acid, Genotoxins (75 mu M hydrogen peroxide, 20 mu M t-butylhydroperoxide and 2.4 mu M mitomycin C) were added to the cells for Ih prior to the end of the 24 h fatty acid incubation period. Control (no genotoxin or fatty acid) treatments were included. No difference was observed in background frequencies of SCEs between controls and fatty acid treatments, thus indicating that these fatty acids per se do not cause DNA damage. The cells incubated with the genotoxins showed increased (P < 0.05) frequencies of SCEs when compared with control frequencies. Cells incubated with genotoxins in the presence of fatty acids also showed significantly higher (P < 0.05) levels of SCEs when compared with control frequencies. When cells supplemented with genotoxins in the presence of fatty acids were compared with cells treated with genotoxins alone, higher levels of SCEs were observed in the former, suggesting that the fatty acids exacerbate DNA damage caused by these genotoxins.