Pressure changes were measured on the skin over the cricoid and thyroid cartilages during intubation of the oesophagus or trachea in 21 consenting patients. A 100-ml bag of saline was firmly fixed to the anterior neck and the pressure changes in the bag recorded. Typical and distinctively different pressure patterns for tracheal and oesophageal intubation were recorded. Oesophageal intubation was accompanied by a statistically significantly higher and longer pressure rise and, most characteristically, by an obvious and sustained rise in baseline pressure. This method is, however, neither practical nor recommended for clinical use in detecting accidental oesophageal intubation. Capnography should always be used during tracheal intubation as an ongoing capnographic waveform provides the only guarantee of correct tracheal placement.