Recurring substernal chest pain is an important clinical problem, causing anxiety for patients and their physicians because of the fear of possible cardiac disease. The differential diagnosis includes coronary artery disease, oesophageal disorders such as acid reflux disease and motility disturbances, musculoskeletal problems, psychological disorders including panic attacks, and a new 'fly in the ointment'--microvascular angina. History alone usually cannot distinguish cardiac from non-cardiac chest pain. After exclusion of significant coronary artery disease, attention must be turned to oesophageal disorders, which may be seen in as many as 50% of these patients. Oesophageal motility disorders, particularly the nutcracker oesophagus, are common, but the relationship between pain and abnormal contraction pressures is not well established. Provocative tests such as edrophonium (Tensilon) and balloon distension help to identify the oesophagus as the source of chest pain but do not direct therapy. Recent studies with ambulatory oesophageal monitoring suggest that gastro-oesophageal reflux may be a more common cause of chest pain than motility disorders. This is an important finding as acid reflux is a treatable problem, while therapies for motility disorders may only worsen reflux disease. The recent observation that oesophageal disorders are frequently associated and interact with psychological disorders such as anxiety, depression, somatization and panic attacks complicates the evaluation and understanding of chest pain. How these various abnormalities may be linked is an unresolved issue. Increased central nervous system stimulation and altered visceral and/or central pain sensitivity could be the common factors. It is hoped that further research into these areas will lead to new understandings of and possible solutions to the complex problem of non-cardiac chest pain.