Biopsies of the tongue and oesophagus were performed on 14 patients with uncomplicated iron-deficiency anaemia before and after treatment with iron. Haemoglobin and serum iron estimations were performed at the same time. Nine patients had clinical evidence of atrophic changes in the tongue before therapy was started. Evidence of regeneration appeared within one or two weeks of starting iron therapy. Two patients showed persistent atrophy. Angular stomatitis and koilonychia were longer in disappearing. Biopsies confirmed that filiform papillae and kerato-hyalin granules are frequently absent from the epithelium of the smooth tongues of iron-deficient patients. Iron therapy is followed by the re-appearance of keratohyalin granules and keratinized filiform papillae. Two patients complained of dysphagia, which disappeared after treatment. No abnormality in the oesophageal epithelium was found in any of the patients either before or after therapy. The relationship of oesophageal carcinoma to antecedent iron-deficiency epithelial changes is considered suspect.