<prompt> The commonest cause of acute pancreatitis isBiliary calculiAlcohol abuseInfectiveIdiopathic  <response>: Major cause of acute pancreatitis is biliary calculi50-70 of patients A careful search of aetiology is must before labelling idiopathic and no more than 20 cases should fall into this category. Bailey Love 26th edition,1127,1128. 