AbstractThe recent need for selective bronchography during bronchoscopy in certain patients, together with paediatric indications for tracheo-bronchography, raises the question as to which contrast medium is both safe and efficient. The purpose of the present experimental study was to define the tissue reaction caused by iotrolan and iopamidol in the bronchi and lungs of rats. 60 animals used in this study were divided into five groups receiving iotrolan 300, iopamidol 370, iopamidol 150, physiological saline and anaesthetic only, the last two acting as control groups. Statistically there was no significant difference in the histological reaction between iotrolan 300, iopamidol 370 and iopamidol 150 compared with the control groups, although iotrolan 300 appeared to result in the least tissue reaction. With its adequately high iodine concentration, low osmolality and relatively high viscosity, iotrolan 300 would appear to be a suitable contrast medium for bronchography.