Forty patients who underwent elective cholecystectomy were allocated randomly to one of two groups. Patients in one group used an incentive spirometer as part of their postoperative chest physiotherapy; those in the other received routine postoperative physiotherapy as dictated by their needs. Each group contained equal numbers of smokers and nonsmokers, and the data from each group were analysed separately. The use of the incentive spirometer did not confer any benefits as judged by clinical evidence of pulmonary complications, pulmonary function tests or length of hospital stay.