Cold-induced vasospasm seen in systemic sclerosis (SS) and Raynaud's phenomenon (RP) has previously been thought to be limited to peripheral skin sites. However, the oesophageal problems seen in SS cannot be sufficiently explained by connective tissue damage/abnormal motility alone. We wondered if temperature dependent ischaemia could occur in the oesophageal microcirculation. We have measured oesophageal temperature variation following oesophageal cold challenge: 50 ml of water at 7 degrees C and 17 degrees C, with 37 degrees C used as control, were introduced into the mid-oesophagus at a rate of 2 ml/s. Temperature was recorded using a thermocouple probe 5 cm above the gastro-oesophageal junction. The test was performed on 14 SS patients, eight patients with Raynaud's disease and 21 controls. The control's rewarming pattern followed a simple exponential curve. This did not vary with temperature or after repeated challenge. In the SS patients the time constant was significantly longer after cold challenge.