A clinical survey on the adverse reaction to a new low osmolality contrast medium (ioxaglate) was performed in 83 patients during June-October 1987. These patients were followed up for 24 hours following angiographic examination. The incidence of adverse reactions due to ioxaglate was 8.4%(7/83). There were no severe reactions, but we encountered nausea, rash and others. The incidence of vascular pain was 6.0%(5/83), we excluded vascular pain from this data because of the difficulty of objectively evaluating vascular pain. The incidence of adverse reactions excluding vascular pain, in our survey, was lower than that (38.8%) reported by Katayama et al.6), because of the low osmolality of ioxaglate. Adverse reations were encountered in 4 of 7 patients after leaving the examination room. Panto et al.8) reported that there were some delayed adverse reactions to contrast media. We propose that clinical surveys of adverse reactions should be discussed in consideration of data obtained after the patient leaves the examination room.