Owing to the wide variety of symptoms, the long clinical course, the inadequate knowledge of the points at which therapeutic action is appropriate and the difficulty of obtaining objective measurements of the treatment results, therapy for systemic sclerosis has to be planned individually. Besides basic recommendations (avoidance of noxious substances, sensible diet, keeping warm, active exercises), physiotherapy and psychological guidance, the therapy is directed at three pathogenetic complexes. - Among the vasoactive substances the prostacyclins, calcium channel blockers and angiotensin-converting-enzyme inhibitors (in the case of complicated renal involvement) are recommended. They inhibit the thrombocyte hyperaggregation and lead to vasodilatation. - The anti-inflammatory substances prednisolone and azathioprine also exert immunosuppressant (and cytotoxic) effect. Their use is indicated in inflammatory, immunologically active forms of systemic sclerosis. - Antifibrotic agents inhibit cross-link formation, prolylhydroxylase, extrusion of collagen from fibroblasts and, thus, collagen synthesis. In addition, they favour the degradation of collagen via the activation of collagenase. Good results have been reported with penicillamine and penicillin G. Pentoxyphyllin leads to vasodilatation and also inhibits collagen metabolism. - Promising agents and procedures for future use include cyclosporin A, CD4 antibodies, photopheresis, interferon-gamma and factor XIII. A critical attitude to therapy and a great deal of patience are necessary to avoid harming the patients, especially as it is often some months before any effects of the treatment are seen.