The organisation team of the Third International DDI (drug-drug interactions) Workshop has expressed great satisfaction with the course of the scientific meeting. The participants of the DDI Workshop commended the very high scientific level of the presentations and valuable and inspiring discussions of the different topics. Without a doubt, the DDI Workshop at Marbach Castle is a well established platform for the annual exchange between experts, scientists, members of the industry and regulatory bodies regarding DDI affairs. This year more than 80 experts from 14 countries attended the DDI Workshop. The speakers came from 6 different countries (USA, Germany, Great Britain, Finland, Sweden, and New Zealand), thereof 5 from the US. They presented scientific news, the content of the draft guidelines and state of the art lectures. The scientific sessions covered different aspects to current regulatory issues, UGTbased DDIs, transporter-based DDIs and pharmacodynamic DDIs.