Objectives To investigate the clinical charactistics of acute pancreatitis(AP),and to summarize the experiences of treatment,improve the diagnostic level and therapeutic effect.Method In this retrospective clinical trial,450 patients with acute pancreatitis admitted to our hospital from January 2000 to December 2004 were enrolled for analysis the etiology,clinical symptoms,diagnostic crieria,complications,therapeutic regimens and prognosis.Results In the 450 patients,366 had mild acute pancreatitis(MAP)(81.3%),84 had severe acute pancreatitis(SAP)(18.7%).As for the etiology,biliary tract diseases accounted for 62.7%,alcoholic-induced 15.3%,hyperlipidemia 12.4%,other factors 12.9%,unknown causes 18% cases.54 cases(12%)were relapsing acute pancreatitis,among which 57.4% suffered from biliary tract diseases.The abdominal pain played a major role in the clinical symptoms(97.3%).82.4% of the patients had serum amylase 3 times higher than the upper normal limit.Around 95.3% had cute pancreatitis confirmed by CT scan.The main local complications of SAP were pancreatic pseudocyst(19.0%).Organ dysfunction/failure was presented in 67.9% of the severe cases.The rate of multiple organ dysfunction(MODS)in SAP was 26.2%,and that of fulminate pancreatitis was 25%.96.7% of patients received antibiotics,and 98.9% received H2RA or PPI.Parenteral nutrition(PN)was given in 88% of the patients,and early enteral nutrition(EN)was performed in 45.2% of the severe cases.14 severe cases underwent continuous veno-venous hemofiltration(CVVH).In order to relieve bile duct obstruction,18 cases underwent endoscopic sphincterotomy(EST)and(or) endoscopic nosal biliary drainage(ENBD).7 severe cases(8.3%)received surgical intervention.Conclusions Biliary tract diseases,alcohol and hyperlipidemia are main etiologic factors of acute pancreatitis.The main causes of AP relapsing may be biliary tract diseases.Serum amylase and CT scan are reliable diagnostic methods for acute pancreatitis.Abdominal pain is the chief syndrome of AP.The complications of SAP are excessive and complicated,which should be attracted considerable attention and treated promptly.It is safe and efficient to perform EN in SAP patients.CVVH is an effective therapeutic option for SAP.The treatment of EST/ENBD for AP patients suffering from bile duct obstruction is safe and effective.Conservative treatment should be an initial choise for SAP.Operation should be performed if there is a specific indication for early surgical intervention,or for conversion to operation.