The multisystem involvement in acute pancreatitis (AP) is a reflection of the pancreatic gland's capacity to produce a number of potent vasoactive peptides, hormones, and enzymes. The various prognostic criteria are early evaluations of these metabolic derangements. The pathogenesis of hypocalcemia, long recognized as an indicator of severity of AP, is multifactorial. Imbalances of parathyroid hormone (PTH)-calcitonin, the interactions of glucagon, gastrin and other pancreatic hormones with PTH-calcitonin, the role of free fatty acids in binding serum calcium with albumin, and the translocation of calcium ion in muscles and liver, have been recently described but remain conflicting theories. Yet, the time-honored theory of calcium-soap formation enjoys wide acceptance. Hyperglycemia, hypoglycemia, and occasional ketoacidosis in acute pancreatitis have been studied thoroughly. The complex cause-and-effect relationship between hyperlipidemia with acute pancreatitis needs further study. The coagulation abnormalities seem to be initiated by activated trypsin, and their role in microvascular coagulation appears to form a unifying hypothesis for major organ dysfunction, but this requires further investigation. Adult respiratory distress syndrome may be the result of active enzymes that digest pulmonary surfactant and/or microvascular thrombosis. The depression of cardiac function and shock are suspected to be secondary to vasoactive peptides such as bradykinin, or myocardial depressant factor, whose structure has yet to be elucidated. The renin-angiotensin alterations and renal complications in acute pancreatitis have received scant attention in the literature. The onset of moderate visual disturbances, or even blindness, in a patient with acute pancreatitis as a result of retinal vessel thrombosis is fortunately uncommon. Rare but interesting are the manifestations such as subcutaneous fat necrosis, arthralgia, and pancreatic encephalopathy. Despite the extensive literature on the complexities of the pathogenesis of complications of acute pancreatitis, there have been very few advances in the prevention and management of specific complications. It is hoped that further work on modification of enzymatic disturbances induced in acute pancreatitis will result in its effective treatment and prevention of serious complications.