Amipaque 280 mg I/ml was compared to Isopaque Cerebral 280 mg I/ml for common carotid injection in twenty patients in a double blind trial. Simple comparison was also performed in examinations with selective external carotid injections. The reaction of the patients to the common carotid injection was mild on the whole but Amipaque caused significantly less discomfort than Isopaque. Selective external carotid injection of Amipaque caused very little discomfort while most patients complained of severe pain when Isopaque was used. No serious side-effect was observed.