Zearalenone is a mycotoxin compound produced mainly by Fusarium species of fungi which is present in cereals cultivated all over the world. The aim of the research was to examine the toxic influence of different doses of zearalenone on liver cells through estimating mycotoxin influence on markers evaluation of biochemical liver damage. The research was carried out on male Wistar rats. The rats were divided into 9 groups of 10 animals each. Group A was orally given 8% ethyl alcohol. Group B, C, D, E was orally given once a day for 10 days a zearalenone alcohol solution properly in dose of 50, 100, 200, 500 microg/kg b.w. Single doses of zearalenone was given to the animals from groups X, Y, Z and W. Control group W - 8% ethyl alcohol, group X dose 1 mg/kg b.w., group Y dose 2 mg/kg b.w., group Z dose 3 mg/kg b.w. For the research, blood was taken from hearts. The blood was centrifuged and the plasma analyzed using spectrophotometric methods: aspartate and alanine aminotransferase, alkaline phosphatase and complete bilirubin. The results of the experiment show that liver cells are exposed to zearalenone activity increased liver aminotransferases (ALT and AST) in blood plasma. Rise of liver aminotransferase level (ALT and AST) in animal's blood plasma after giving zearalenone may confirm the hepatotoxic influence of this mycotoxin. Short-lasting zearalenone influence does not cause changes in the liver aminotransferases.