Cytokines are important immunoregulatory mediators. Their contribution to the pathogenesis of acute and chronic gastroenterological disorders is obvious. Increased expression of interleukin-1 (IL-1), interleukin-6 (IL-6) and tumor necrosis factor (TNF) can be detected in inflammatory bowel disease. During the last few years it has also been recognized that activated leukocytes have an important role in the multisystem involvement of acute pancreatitis. Activation of leukocytes is an early event during severe acute pancreatitis, and it may be a pathogenetic factor in the severity of the disease. The review summarizes the recent findings in the field of inflammatory cytokines with particular attention of TNF, IL-1, IL-6, and IL-8 during severe acute pancreatitis and underscores the role of the activated leukocytes in the pathogenesis of complicated acute pancreatitis.