Contrast material-enhanced computed tomography (CT) was performed in 100 patients. Fifty milliliters of contrast material was intravenously injected by hand and followed by a drip infusion of 100 mL of contrast material. Venous air embolism occurred in 23% of the patients. The amount of embolism was minimal in 20 patients and moderate in three. Although large amounts of embolism have been reported to be associated with considerable morbidity and mortality, none of the patients in this study had immediate or delayed complications as a result of the small degree of embolism. The locations of the emboli were in the subclavian or axillary vein in nine, right or left brachiocephalic vein in three, internal jugular vein in two, superior vena cava in two, right ventricle in two, and main pulmonary artery in 12 patients. In patients at high risk for cerebral air embolism, such as those with intracardia shunts or pulmonary arteriovenous malformations, extreme caution should be used-even in the routine administration of intravenous fluids or contrast media-to prevent venous air embolism and resultant neurologic deficits.