The aim of the study was to investigate the effect of LPS injections on non-specific mechanisms of immunity in pigeons. On the first day of observation the experimental birds (n=18) were intravenously injected with Escherichia coli LPS (10 microg/kg b.w.), while the control animals (n=6) received in the same way apyrogenic physiological saline. On the second and the third day of the experiment LPS in the same doses was injected again. Four and a half hours after the saline and each pyrogen administration blood samples were collected from the control and experimental pigeons. The total protein, gamma globulin, lysozyme, acute phase protein (Cp, CRP, Tf, ferritin, Alb) and selected trace element (Fe, Cu, Zn) concentrations were investigated. The obtained results showed the increase in the concentration of total protein, Cp, CRP and Tf in endotoxin fever resulting from LPS injection in pigeons. In contrast, the concentration of gamma globulins, ferritin and A1lb were decreased in response to the first LPS injection. However, the consecutive injections of LPS caused a decrease in the concentration of total protein, CRP and Tf. In opposition to those results, a significant rise in the lysozyme and ferritin concentrations was observed. On the other hand, the first LPS injection caused a decline in the iron and zinc concentrations which remaining lower than the control values following repeated administration of LPS. On the contrary, the copper concentration increased successively in response to the next LPS injections.