This randomised double-blinded study compared the cardiovascular stability and rate of recovery when propofol infusions with or without alfentanil were used to provide anaesthesia for rigid oesophagoscopy and (or) bronchoscopy. Forty-six patients were allocated randomly to receive either alfentanil 10 micrograms/kg or saline just before a rapid sequence induction with propofol. Suxamethonium 1 mg/kg was given and infusions of suxamethonium 10 mg/minute and propofol (10 mg/kg/hour for 10 minutes, 8 mg/kg/hour for 10 minutes and then 6 mg/kg/hour thereafter) were started. There were 23 patients in each group with no significant demographic differences between the groups. A significantly mean lower induction dose of propofol was needed in the alfentanil group (1.7 mg/kg compared to 2.2 mg/kg). Cardiovascular measurements were made on the ward pre-operatively, just before induction, just after induction, just after intubation, and at 3-minute intervals thereafter. Arterial pressure was significantly lower during the procedure in the patients who received alfentanil and there was a significant incidence of hypotension. There was no significant difference between the groups in respect of heart rate, with a significant increase in both groups just after intubation compared to the baseline values. Recovery from anaesthesia was assessed using the critical flicker fusion threshold. No differences were found between the groups and patients in both groups had returned to baseline values by 60 minutes. No patient had any recall of intra-operative events, and there were no other adverse effects of any significance.