This report describes a patient who developed pulmonary toxicity, mani
fest by dyspnea on exertion, a low pO(2), a normal FEV(1) and FVC, and
a low DLCO while receiving 5-fluoro-2'-deoxyuridine (FUDR) by intermi
ttent continuous i.v. infusion. No other cause of his low DLCO could b
e identified. The dyspnea on exertion and DLCO improved gradually afte
r the FUDR was discontinued. This case was felt to represent a previou
sly undescribed toxicity of the continuous i.v. infusion of FUDR.