In 1998 the British Society of Gastroenterology (BSG) published UK guidelines on the management of acute pancreatitis. A planned revision after two years was anticipated. The BSG as the prime sponsor of these guidelines initiated a review process in 2000. These guidelines are part of a series sponsored by the BSG, and a policy decision was taken in that organisation to modify the format of the guidelines, to enable the dissemination of summary documents listing the main conclusions, recommendations, and audit standards, with a subsidiary document reviewing the evidence in detail. The present document uses this new format; in addition it focuses on developments since 1998. Although some revisions are necessary, the main evidence base was well reviewed previously, and remains valuable.