Thirty-five patients with diffuse systemic sclerosis were studied in a randomized, placebo-controlled, double-blind study. Seventeen patients received intravenous dexamethasone "pulse" therapy, while 18 patients received placebo. Each "pulse" consisted of 100 mg dexamethasone in 250 ml 5% dextrose infused intravenously over 1 h. Pulse therapy was repeated every month for 6 months. Assessment of disease status with various parameters was done at entry and at completion of trial, i.e. after 6 months. Significant improvement in skin involvement was seen in the study group, with the total skin score (TSS) decreasing from 28.5 +/- 12.2 to 25.8 +/- 12.8, while in the control group, TSS increased from 30.6 +/- 13.2 to 34.7 +/- 10. Similarly, significant improvement was noted in the flexion index. Other parametres that included extension index, maximum oral opening, range of movement of joints, functional disability score, Raynaud's phenomenon (frequency and duration), ESR, proteinuria, chest X-ray, ECG, lung function tests, barium swallow and antinuclear antibody were unchanged. Adverse effects of therapy were limited to an increased incidence of minor chest infections. It is concluded that intravenous pulse dexamethasone may be useful in the treatment of diffuse systemic sclerosis.