In a double-blind randomised trial an infusion of doxapram, 2 mg per min for 6 h immediately after surgery and repeated on the first postoperative day, or the same volume of saline, was given to 39 patients who underwent upper abdominal surgery and who were at high risk of postoperative day, or the same volume of saline, was given to 39 patients who underwent upper abdominal surgery and who were at high risk of postoperative pulmonary complications. The patients were assessed pre-operatively and during the first 5 postoperative days by physical examination, spirometry, blood-gas analysis, and chest radiography. Postoperative pulmonary complications were defined as temperature over 38 degrees C for 2 days, abnormal auscultation, pathological radiography, and/or productive cough. Data from 16 patients per group were analysed. Significantly more patients in the placebo group had three criteria of postoperative pulmonary complication compared with the doxapram group (63% vs 19%). The doxapram group also had higher PaO2 postoperatively.