The mutagenicity of acrolein, allyl alcohol, glycidol and propionaldehyde was measured in V79 cells as resistance to 6-thioguanine. Acrolein was tested with and without fetal bovine serum (FBS) (10%; v/v) during the 2 h incubation period. The concentration of FBS did not affect acrolein toxicity but its mutagenicity declined as the concentration of FBS in the medium rose. Allyl alcohol (AA) was as mutagenic as acrolein (ACR). Glycidol was less mutagenic than AA and ACR. Propionaldehyde was not mutagenic at 1 microM; it was toxic at 2 microM. The data suggest that the mutagenicity of these compounds is mediated by their bifunctional nature whereas their cytotoxicity is mediated by the aldehyde function.