After evaluation of the patient's clinical condition and appropriate premedication is seems reasonable to suggest for: 1. Endoscopic procedures involving the gastro-intestinal tract: slow, titrated induction, using 0.5 to 1 mg.kg-1 of propofol, until the required level of sedation has been achieved; this may or not be preceded by the injection of a low dose of midazolam (0.02 to 0.03 mg.kg-1) or of alfentanil (5 micrograms.kg-1); maintenance is achieved by bolus injections of 20 mg (up to 0.5 mg.kg-1); maintenance of spontaneous ventilation, with oxygen administration is the rule; SpO2 is monitored routinely; anaesthesia has to be performed according to the recommendations of the French Society of Anaesthesia and Intensive Care (SFAR) and the anaesthetist must be prepared to manage any incident during the endoscopy and the recovery period. 2. Procedures involving the biliary tract and the oesophagus, which require deeper anaesthesia: induction should again be titrated using a very slow infusion, with doses ranging from 0.9 to 2.2 mg.kg-1); the maintenance requires a continuous infusion, doses ranging from 4 to 6 mg.kg-1.h-1 when propofol is administered alone and from 4 to 12 mg.kg-1.h-1 when combined with an opioid; continuous oxygenation is necessary using a nasal airway; the need for intubation depends on the type of procedure and the status of the patient; the same monitoring devices and similar safety measures are required during and after procedure as for any anaesthetic or sedation, especially when it is performed in day-case patients or outside the operating theatre.