Mean pulmonary function was significantly decreased in 57 patients during excretory urography. Patients with a history of allergy had significantly greater mean decreases in flow rates than those without. Twelve did not have significant decreases in pulmonary function after needle puncture and i.v. injection of 5% dextrose in water. Eight healthy subjects did not have significant mean decreases after i.v. injection of 5% saline. Most patients undergoing excretory urography have bronchospasm that is greater in magnitude in those with a history of allergy.