Arterial oxygen tension (Pao2), carbon dioxide tension (PaCO2), and vital capacity were measured preoperatively and one day postoperatively in patients with chronic hepatic cirrhosis having elective oesophageal injection sclerotherapy under general anaesthesia. The results were compared with the same measurements made in patients with chronic cirrhosis anaesthetised and scheduled to have injection sclerotherapy under general anaesthesia but who, because of variceal obliteration, only had an oesophagogastroscopy. In the injected group PaO2 decreased by 9.3 (3.0) mm Hg (1.2 (0.4) kPa) (mean (SEM)) (p < 0.02) but in the controls did not change. The difference between the two groups was significant (p < 0.02). Vital capacity decreased by 0.39 (0.08) litres (BTPS) (p < 0.01) after injection sclerotherapy but in the controls did not change. Again the difference between the two groups was significant (p < 0.02). In the injected group there was a significant correlation between the change in PaO2 and the percentage change in vital capacity (r = 0.787, p < 0.01) but no such relation was seen in control subjects. These results suggest that oesophageal injection sclerotherapy is associated with a restrictive defect in respiratory function one day after the injection caused, possibly, by sclerosant embolising to the lung.