Vasoactive drugs are widely prescribed in France. Over the last few years, some of these molecules have been evaluated by controlled clinical trials based on subjective assessment of their effects on the arterial or venous disease. Paraclinical investigations performed with a view to provide clinical pharmacological or physiopathological information give an indication as to the mode of action of these drugs but cannot, under any circumstances, be substituted for controlled clinical trials implying the inclusion of large patient population groups.