The aims of this study were: (1) to compare which analyte, among CRP, PCO and PON1, better differentiates dogs with sepsis from those with polytrauma or from healthy dogs; (2) to preliminarily investigate the possible role of CRP, PCO or PON1 in predicting the prognosis of septic dogs, by assessing if results obtained at admission for each analyte may be associated with a negative clinical outcome. Here, PON1 is linked to Sepsis.