The role of 5-aminosalicylic acid (5-ASA) therapy in Crohn´s disease is unclear. The aim of the study was to assess retrospectively the outcome of the 1st course of 5-ASA monotherapy with emphasis on 5-ASA dependency in a consecutive cohort of 537 Crohn´s disease patients diagnosed and treated at Herlev University Hospital from 1953 to 2007.