The course of chronic inflammatory bowel diseases is highly variable and prediction of relapse remains difficult. Doppler sonography is a newer, non-invasive method to assess the hyperdynamic splanchnic blood flow that is characteristic of acute inflammation. Its role in the analysis of disease activity is still limited and its application restricted to specialized units. However, improved spatial resolution by power Doppler ultrasound, with or without the use of contrast agents, allows a very early detection of mucosal and transmural inflammatory lesions. Still more important, the repeated quantification of mesenteric blood flow enables the prediction of relapse at six months after steroid-induced remission. Future studies should clarify whether the combined application of available methods will allow a more calculated and finally more effective therapy.