The value of quantitative (venous-occlusion plethysmography), semiquantitative (ultrasound-Doppler method; walking distance; duration of bicycle ergometry) and metabolic (lactate, pyruvate) tests was assessed in 41 patients with arterial occlusive disease of the upper leg type. It was demonstrated that blood pressure measurement using the Doppler method is of great importance. Significant differentiation between normal and impaired blood flow was obtained with venous-occulsion plethysmography for both "first flow" and "peak flow". The diagnostic value as to the degree of peripheral arterial disease was similar for plethysmography and Doppler methods. Duration of bicycle ergometry provided an important pointer to the degree of functional impairment of the affected extremity. The level of lactate and pyruvate in femoral venous blood is suitable more for serial controls and assessment of treatment in patients in whom haemodynamic studies have already clarified the diagnosis of impaired blood flow.