The purpose of this study was to compare the effectiveness of a simple technique of active lung reexpansion through a fiberoptic bronchoscope, using a large volume syringe, with that of the conventional fiberoptic bronchoscope suction. Thirty consecutive patients with atelectasis were divided at random into two groups: with and without active inflation. The two groups were similar as regards age, sex-ratio, side and area involved in atelectasis. The group without inflation was less hypoxaemic than the other group (PaO2 202 and 140 mmHg respectively). Early and lasting improvement in chest X-ray and arterial blood gases occurred in both groups, but patients were significantly more improved during fiberoptic inflation. No pneumothorax or haemoptysis was observed during the procedure. These data prompt us to recommend active inflation instead of fiberoptic bronchoscopy suction alone for the emergency treatment of patients with severe hypoxaemic atelectasis.