In daily routine diagnosis, there are few parameters available to monitor critically ill patients and to control the course of therapy in severe inflammations. There are also few reliable parameters differentiating acute bacterial infection from other types of inflammation. Most of the presently used indicators of the inflammatory response, like body temperature, white cell count, erythrocyte sedimentation rate or C reactive protein are unspecific parameters with changing reliability. Procalcitonin is a diagnostic parameter of bacterial infections with systemic reaction of the organism. It is an innovative diagnostic parameter with feature different from other presently available indicators of the inflammatory response. The incidence of noninfectious systemic inflammatory response syndrome associated with coronary artery bypass surgery and the potential role of several inflammatory parameters as early markers of pulmonary dysfunction induced by cardiopulmonary bypass were investigated. Procalcitonin seems to be appropriate parameter indicating the early development of severe noninfectious systemic inflammatory response syndrome and for predicting pulmonary dysfunction secondary to cardiopulmonary bypass. Hence, the review of the data of different authors may lead to the conclusion that because of wide spectrum of indications procalcitonin concentration can be used for differential diagnosis of bacterial versus non-bacterial inflammation, as monitoring parameter in critically ill patients, the course of disease, treatment control evaluating the effectiveness of antibacterial treatment, for evaluation of high risk patients to see if there are no postoperative bacterial complications as a prognostic indicator.