A prospective study of 45 patients with venous insufficiency. The patients were divided into four different groups that were comparable in venous function, age and sex distribution. The effect of four different conventional compression stockings was evaluated by their clinical effect and the effect upon the musculo-venous pump as assessed by ambulatory strain-gauge plethysmography, over a 6-week treatment period. In this patient category, there could not be demonstrated any additional benefit of increasing compression, and patient acceptability was concomitantly reduced with increasing pressure. The pressure exerted by the stockings was assessed by the Borgnis Medical Stocking Tester, and pressures were found to increase in the upright position with an increase in the concomitant pressure gradient between ankle and knee.