There is no doubt that gastro-oesophageal reflux can cause a chronic cough. However, how frequently reflux is the underlying cause in patients presenting to the readers of Thorax is a matter of much debate. This confusion can be laid squarely at the door of the gastroenterologists who have taken one symptom of acidic reflux—heartburn—and made it the sine qua non for gastro-oesophageal reflux disease. This characterisation of gastro-oesophageal reflux disease as heartburn has led to the denial of the non-acid extra-oesophageal symptoms of reflux. In reality, however, reflux is almost universal in humans because our upright posture has disrupted the anatomy of the lower oesophageal sphincter. Measurement of electrical impedance within the gullet in fact shows that only a small number of reflux episodes are acidic (below pH 4)¹ and, while it takes a lot …