Midazolam is widely used as a sedative agent to produce amnesia in patients undergoing fibre-optic bronchoscopy. However, if a patient does not receive sufficient local anaesthesia, continuous severe cough and physical movement may interrupt the procedure and reduce its safety. We therefore examined whether codeine phosphate is a useful premedication for bronchoscopy. The study design was a randomized comparison between codeine phosphate and a placebo in patients undergoing light local anaesthesia and midazolam sedation. We used low dose local anaesthesia (5 ml of nebulized 2% xylocaine) on the assumption of insufficient local anaesthesia. Patients were allocated to receive codeine phosphate 0.4 mg kg-1 or a saline placebo 60 min before they were sedated with i.v. midazolam. If the patients exhibited severe cough during bronchoscopy, intrabronchial supplemental local anaesthesia (2% xylocaine solution in 1 ml increments) was instilled via a bronchoscope to the trachea and segmental bronchi to suppress the cough. The dose of supplemental xylocaine was assessed and the requirements were significantly lower in the codeine group compared to the placebo group: 36.4 +/- 10.2 mg vs. 95.1 +/- 24.6 mg, respectively. After bronchoscopy, patients were interviewed by a doctor to assess their willingness to undergo a repeat procedure if one was clinically indicated, but no significant difference was observed between the two groups. If local anaesthesia is insufficient, midazolam together with codeine phosphate premedication is useful for both the patient and the bronchoscopist.