In the present work the influence of the administration of industrial emissions from a zinc and copper plant on aspartate aminotransferase (AST), alanine aminotransferase, gammaglutamyl transferase, creatine phosphokinase (CK), total bilirubin, serum zinc levels and the genetic apparatus was studied on seven ewes. Each animal was given a dose of 31.99 g of emissions per day. The first and the last animals died of zinc intoxication on days 42 and 58, respectively. Significantly increased zincemia could be observed from day 8 of the experiment (P < 0.01). In the enzymes under investigation, the most pronounced effects of the emission were seen in AST and CK activities. In comparison with the starting levels, AST values revealed significant differences on days 37 and 58 (P < 0.05 and P < 0.01, respectively), and CK on day 58 (P < 0.01). Significantly increased bilirubinemia (P < 0.01) could be observed from day 8 of the experiment. In the period prior to the first gavage of emission and day 30 of administration no significant increase of chromosome breaks per cell was observed in the experimental sheep. The genotoxic effect of the emission was also stated on the basis of recombination frequency visualized by means of the sister chromatid exchange test; on day 30, the increase of these disturbances revealed statistical significance (P < 0.01).