The use of nebulized lignocaine, with and without intravenous diazepam premedication, was compared with lignocaine given by bolus in 52 patients undergoing fibreoptic bronchoscopy (FOB). Changes in airflow, cardiac rhythm, and transcutaneous PO2 were recorded, and patient acceptability, blood lignocaine levels, and the duration of the procedure were also monitored. Nebulized lignocaine alone provide adequate anaesthesia and the procedures were performed more quickly (P less than 0.05) than when bolus lignocaine was used. Nebulized lignocaine without diazepam was acceptable to the patients and was not associated with the significant (P less than 0.03) falls in transcutaneous PO2 which followed diazepam administration. Nebulized lignocaine, with and without, diazepam premedication is a safe, effective and acceptable method of inducing topical anaesthesia for FOB.