Is it advisable to go back from bedside to the bench? During the last decade, few topics encountered such a broad interest in bio- gy and medicine as angiogenesis. The amazing ability of the body to restore blood flow by induction of blood vessel growth as part of an adaptive process has alarmed physicians dealing with diseases in which angiogenesis is either exaggerated (as in tumors) or too slow (as in ischemic diseases of heart and brain). Not surprisingly, pro- and antiangiogenic strategies have found their way into clinical trials. For instance, for the USA, the NIH website in early 2004 displayed 38 clinical studies involving either pro- or antiangiogenic th- apies. Given the expected overwhelming wealth of clinical data, the question may be asked whether further exploration of biological mechanisms is required or whether results from the bedside are instructive enough to proceed. This question depends also on the progress of pro- and antiangiogenic clinical trials. In the following, I give a short overview about some of the progress that has been made in this field. Since Judah Folkman proposed antiangiogenic tumor therapy thirty years ago, it has become increasingly evident that agents which interfere with blood vessel formation also block tumor progression. Accordingly, antiangiogenic therapy has gained much attention as a potential adjunct to conventional c- cer therapy.