Oesophageal motility and lower oesophageal sphincter (LOS) competence were investigated in 13 patients with progressive systemic sclerosis (PSS) and in 16 patients with localized scleroderma (LS) by means of oesophageal manometry and 24-h pH monitoring of the distal oesophagus. Results were compared with those of a control group consisting of asymptomatic volunteers. Marked abnormalities in oesophageal motility and in acid exposure in the distal oesophagus were observed in PSS patients only. The mean resting pressure of the LOS was 10.1 +/- 1.5 mmHg in PSS, 21.4 +/- 1.1 mmHg in LS, and 23.8 +/- 2.0 mmHg in asymptomatic controls. Overall sphincter length was 24.1 +/- 3.4 mm in PSS, 31.1 +/- 1.6 mm in LS, and 39.0 +/- 2.0 mm in the control group. Spincter abdominal length was 12.1 +/- 2 mm, 15.4 +/- 1 mm, and 25.0 +/- 1 mm, respectively. The amplitude and duration of oesophageal waves were markedly reduced at 5, 10, and 15 cm above the LOS in PSS patients, with only the upper part of their gullet being spared. An abnormal acid exposure in the distal oesophagus was observed in 84.6% of PSS patients, whereas only 18.2% (2 of 11) of pH-tested LS patients had an abnormal 24-h pH test. These data show that a marked oesophageal involvement is present only in the systemic form of scleroderma. Oesophageal tests may be useful for a circumstantial diagnosis whenever the diagnosis of PSS is uncertain; however, their use does not seem to be justified as routine in patients with LS.