The earlier an arterial occlusive disease is recognized and intensively treated the more favorable the longterm prognosis. Such therapy includes to an equal extent the elimination or treatment of "risk factors" and intensive collateral training. Assessment of the course of this, per se chronic, disease requires longterm observation. Contrary to general opinion, however, neither clinical angiological findings nor most of the customary angiological methods can give a satisfactorily reliable judgment as a rule: only venous obstruction plethysmography and the Doppler ultrasonic flow measurements provide objective figures. The latter are suitable for general practice with regard to both expenditure of time and money and to the accuracy of their measurements.