Background and aims The role of 5 aminosalicylic acid (5 ASA) in Crohns disease is unclear The outcome of the first course of 5 ASA monotherapy with emphasis on 5 ASA dependency was retrospectively assessed in consecutive cohort of 537 Crohn s disease patients diagnosed 1953-2007 Methods Following outcome definitions were used Immediate outcome (30 days after 5-ASA start) defined as complete/partial response (total regression/improvement of symptoms) and no response (no regression of symptoms with a need of corticosteroids, immunomodulator or surgery) Long term outcome defined as prolonged response (still in complete/partial response 1 year after induction of response), 5 ASA dependency (relapse on stable/reduced dose of 5 ASA requiring dose escalation to regain response or relapse