Making an analysis of those exposed, connected with the diagnoses of day 1 (preoperatively), days 3 and 7 (postoperatively), we have noticed that the diagnostic value of IL–6 and TNF alpha for sustaining the severity diagnoses, suited the period in which the dosage has been made (peritonitis with systemic inflammatory response syndrome with or without septic complications). This evidence concerns the gene TNF and systemic inflammatory response syndrome.