The effect of Arwin^® on peripheral arterial occlusive disease has been studied in two multicentre trials. In the first, in cases of severe peripheral arterial circulatory disorders of the lower extremities with permanent rest pain (stages III and III + IV according to Fontaine) Arwin^® had a better intravenous therapeutic effect than anticoagulant treatment. A further trial was done to investigate whether subcutaneous administration of Arwin^® would have an effect superior to classical conservative therapy with vasodilator drugs in this type of disease. The results were assessed by sequential analysis. Arwin^® was again shown to be a much better treatment. Problems of medical documentation and statistics are discussed in relation to the value of sequential analysis.