Thiopurine drugs are widely used as immunomodulatory and corticosteroid-sparing agents in inflammatory bowel disease. Despite being old drugs, a renewed research and clinical interest in their application has emerged during the last decade. The application of pharmacogenetic insights and metabolic monitoring, together with treatment strategies in combination with anti-TNFalpha-antibodies and possibilities to modulate their metabolism, has paved the way to a "modern" use of the thiopurines. These aspects are briefly overviewed herein.