Objectives: The aim of the present study was to clarify the possible long term effects in the course of different haemodilution regimes according to the tissue oxygen supply in the lower limb muscle of patients with intermittent claudication. Methods: In order to simulate the situation of intermittent claudication muscle tissue pO(2) measurements were performed before and after a standardized pedal ergometric test. Muscle tissue pO(2) readings were performed using micro-pt-needle electrodes at a work load of 5.7 +/- 0.2 Watt. We performed hypervolaemic haemodilution as well as isovolaemic haemodilution intraindividually and in order to compare these different regimes we have chosen the situation, when the haematocrit had returned to the pretreatment values. Results: Observing 4 weeks after the end of isovolaemic haemodilution the red blood cell aggregation is significantly decreased, whereas the other haemorrheological variables remained unchanged. Furthermore muscle tissue pO(2) values are increased at rest without improvement of the exercise-induced muscle tissue pO(2). In contrast there is no effect on haemorrheological variables as well as muscle tissue oxygen supply at rest and after pedal ergometric exercise test after the end of hypervolaemic haemodilution. Conclusions: Our results suggest no benefit in the course of a long-term hypervolaemic haemodilution therapy in patients with intermittent claudication. In contrast after isovolaemic haemodilution there was found an increase in muscle tissue oxygen supply at rest without changing of the exercise-induced pattern. In our opinion isovolaemic haemodilution is to prefer in the course of long-term haemodilution therapy.