Reactions to urographic contrast media occurring after the patient had left the department were studied by giving patients a questionnaire to complete. 841 questionnaires were returned (about 80% of those issued). 70% of patients had no delayed reactions and 7% expressed a positive response to urography i.e., found the procedure interesting and not unpleasant; 13% had arm pain, 5% a rash and 14% had a variety of reactions, many of which were the same as those described in iodism. Women had significantly more rashes (7%) than men (4%) and those media containing the meglumine or iodamide ions caused more rashes than other media. Conray 420 caused more arm pain than Conray 280 or the non-ionic media, which would be expected from the known effects on vascular endothelium. Symptoms of iodism were equally common from the various contrast media.