Multichannel intraluminal impedance is a new technique for evaluating esophageal function and gastroesophageal reflux disease (GERD). This technique relies on the monitoring of electric conductivity in the esophagus though electrodes, and on changes developing in this variable as a result of bolus passage. The proximal distribution and duration of non-acid reflux events can now be quantified, and combined manometry defines the effectiveness of esophageal body function, until now only indirectly evaluated with pH changes. We discuss the case of a woman with persistent cough in whom intraesophageal multichannel impedance demostrates a minor acid reflux that could not be demonstrated with other diagnostic methods previously, and how this technique excludes any association between cough and non-acid reflux.