Patulin is a mycotoxin produced by many species of the fungi. The toxic action of patulin mainly affects the gastrointestinal tract and the immune system. The aim of our work was to assess the toxic effect of patulin, based on the analysis of interleukin IL-6 concentrations in the liver of test animals loaded with different doses of this mycotoxin. The research was conducted on mice which were assigned to 6 groups receiving different doses of active substances. After decapitation, their livers were taken for laboratory testing. Our studies have shown that chronic intoxication with patulin at 0.1 LD50 leads to a statistically significant increase in IL-6 concentration in the liver of the animals. We also found that the loading of experimental animals with a single dose of patulin in the amount of 0.5 LD50 and 0.2 LD50 also leads to a statistically significant increase in this interleukin in the examined organ. There was no difference in its concentration compared to the control group only after the single dose of the lowest concentration of patulin, while the highest average IL-6 concentration was recorded in the liver of animals loaded with the highest single dose of patulin. After applying, one-time doses of this mycotoxin in the amount of 0.2 LD50 and 0.1 LD50, the mean concentrations of IL-6 in the liver in animals from these groups were statistically significantly lower. In conclusion, the analysis of the obtained results confirms the fact of the hepatotoxic effect of patulin.