Oesophago-pharyngeal reflux is widely accepted as an aetiological factor in many laryngeal and lower respiratory tract diseases. This study aims to establish normal reference ranges for pharyngo-oesophageal pH and pressure. Twenty-five asymptomatic healthy volunteers underwent ambulatory pharyngo-oesophageal pressure and pH-metry. Acid exposure times were very low. Only one subject showed any evidence of oesophago-pharyngeal reflux during recumbency. Two distinct upper oesophageal sphincter pressure patterns were observed during recumbency-one with episodic dry swallows and moderate tonic pressures, the other with almost complete manometric quiescence. Negative results, i.e. the exclusion of abnormal cervical reflux, appear to be more achievable than quantifiable positive results, but this is not absolutely clear from our results. Categorisation of an individual as having abnormal upper pH-metry requires use of a synchronous pharyngeal probe. pH-metry is likely to be of value in establishing the role of reflux in relation to laryngeal or respiratory disease.