The laryngeal mask, provides a totally patent airway when positioned in the hypopharynx with remarkable patient tolerance, even at very light planes of sedation. The major advantages of the laryngeal mask are its ease of insertion, the absence of contact with the vocal cards, and the fact that it frees the hands of the anesthesiologist. Contraindications to its use result from its failure to seal the airway against regurgitation of gastric content. Laryngeal masks can be used easily instead of facial masks during anesthesia with spontaneous ventilation and, with experience, can be used for longer procedures using controlled ventilation. Suspected difficult intubation and establishment of a patent airway in emergency conditions are good indications for the use of this device. The laryngeal mask does not replace endotracheal intubation. It can, however, permit better management of the airway while waiting for personnel trained in endotracheal intubation. The nature of the pulmonary pathology seen in intensive care patients limits use of the laryngeal mask during intensive care. In the operating room few complications have been described, and postoperative discomfort is minimal. The laryngeal mask is a device positioned in the hypopharynx which allows separation of the digestive tract from the airway, without violation of either the larynx or the upper oesophageal sphincter. An endotracheal tube, because of its positioning, hinders normal glottic movement and narrows the airway.(ABSTRACT TRUNCATED AT 250 WORDS)