Haemodilution is an efficient conservative therapy of peripheral arterial occlusive disease. Already a single isovolaemic haemodilution (replacement of 500 ml blood for Haes* 0.5 10%) increases the pain-free walking distance by 85%. These effects can be maintained by a constant therapy over six weeks and following haemodilution once or twice per month. The haematocrit values should be between 38 and 42%. The haemodilution should be done hyper- or isovolaemically. Not more than 250 ml blood and 500 ml Haes should be infused during one session in order to avoid hypovolaemia. This means an infusion of 250 ml Haes, venesection of 250 ml blood via the same access and then infusion of the remaining 250 ml. The whole procedure should not last more than one hour. Blood pressure, heart rate, lung auscultation and percussion as well as creatinine values has to be controlled during an intensive therapy. If the hydroxyethyl starch concentration exceeds 150 g per week pruritus may occur in singular cases, if the concentration exceeds 700 g per week it is observed in 50% of the cases. Provided the preventive maesures are observed haemodilution is an efficient and good therapy which also increases the compliance to practice vascular exercise.