Significant scientific progress has been made in recent years in the aetiopathogenesis of chronic inflammatory bowel diseases (IBD), that has changed or will change in the future the diagnostic and therapeutic approach in these diseases. The relevance of classical conventional IBD therapies has been critically re-evaluated under criteria of evidence-based medicine approaches. On the other hand, new therapeutic options have emerged. These include modern immunomodulators, biologics, probiotics, worm eggs and extracorporeal therapies. The clinical relevance of these new modalities is often difficult to assess for physicians who do not work frequently with IBD patients. This book, the proceedings of the Falk Symposium No.153 on ‘Immunoregulation in Inflammatory Bowel Diseases – Current Understanding and Innovation’, held May 6–7, 2006 in Berlin, Germany, critically discusses established and emerging new concepts in the diagnosis and treatment of IBD, reflecting the recent advancements in the aetiopathogenesis of these diseases. Controversial problems, such as the optimal therapeutic strategy (step-up versus top-down), therapy-associated side-effects and optimal control and selection of IBD therapies, are addressed by an internationally-renowned team of authors. The book will be essential reading for both basic scientists and clinicians.