Although parenteral contrast agents are now widely used in the central nervous system, progress in the development of applications in the remainder of the body has been slow. Both intravenous Gd-DTPA and magnetic iron oxide particles have many potential applications but the former will probably require faster imaging techniques and the latter will require reformulation to produce a less toxic preparation. In spite of these problems methods have been developed for the diagnosis of myocardial infarction, breast carcinoma, and musculoskeletal tumors. Interesting preliminary results are available for other applications of contrast agents in the body and many of these are likely to become routine over the next 5 years.