The pressure transmitted to the oesophageal wall was measured in 3 patients with bleeding oesophageal varices controlled by balloon tamponade. The pressure transmitted was considerably lower than the pressure inflated, and all patients suffered retrosternal pain when the transmitted pressure rose to 40 mm Hg. Furthermore, the diameters of oesophageal balloons of 23 Sengstaken-Blakemore tubes (Rüsch) were measured at increasing inflation pressure. The compliance was very high. All balloons bulged at median inflation pressures of 75 mm Hg, and the pressures fell to a median of 55 mm Hg, unaffected by further inflations. The diameter at 40 mm Hg was 27.3 mm. In the light of these observations it remains still to be explained how the oesophageal balloon of the Sengstaken-Blakemore tube effects haemostasis in bleeding oesophageal varices.