Analysis of clinical data, results of treatment, and the development of systemic inflammatory reaction (SIR) in 100 patients with sterile or infective pancreonecrosis and pancreatogenic necrosis demonstrated a phase-wise pattern in the development of inflammatory and septic process in pancreonecrosis. The development of inflammation and sepsis in such patients is determined by the extent of involvement, infection of necrotic zone, and disease duration. SIR, shock, and polyorgan failure are the cardinal components in the pathogenesis of various phases of pancreonecrosis. Detection of signs of SIR and sepsis are needed for individual and urgent evaluation of patient's state. The scale for evaluating the severity of patient's physiological condition and index of involvement of abdominal and retroperitoneal organs are the most accurate, sensitive, and quantitative characteristics for evaluating the patient's condition and the course and outcome in pancreonecrosis.