Three hypotheses have been proposed for the decreased incidence of Plummer-Vinson disease: non-existence, identity with inlet gastric mucosa of the oesophagus and disappearance of the predisposing condition(s). We examined these possibilities by reviewing our understanding of the syndrome. The early framers disagreed on the cause, but many thought it was a precursor for upper oesophageal carcinoma. Four explanations arose to account for the pathogenesis: iron deficiency; nutritional deficits; autoimmunity; and gastric lesion. We believe the decline in recognition paralleled the improve of dietary status and the treatment of sideropenic anaemia with inorganic iron salts.