A case of life-threatening adverse effects following intravenous administration of a non-ionic contrast medium is reported. The patient, a 68-year-old diabetic hypertensive male with dyspnoea and cough had an abnormal chest radiograph, revealing congestive heart failure and an enlarged right hilum. Computed tomography (CT) of the chest was performed using 100 cm3 of intravenous iopamidol. Within half an hour the patient developed abdominal cramping, vomiting, and diarrhoea, followed by hypotension, tachycardia, fever to 40 degrees C, and delirium. His course was complicated by disseminated intravascular coagulation, rhabdomyolysis, renal failure, respiratory arrest, and atrial fibrillation. There was no evidence of infection, neoplastic disease, or myocardial infarction. Over the next month the patient slowly recovered. One other case report implicates a contrast agent with a similar syndrome. The features of this case fulfil the criteria for a probable adverse drug reaction of a type and severity rarely encountered.