Calcium dobesilate was studied in a double-blind trial in 30 normal subjects and in 30 patients with chronic venous insufficiency (CVI). There were no significant alterations in the normal subjects. In patients with CVI the active drug gave significant improvements (p less than 0.01) in the measured volume of the foot and lower limb, in clinical tenderness (p less than 0.05), and in most of the symptoms (including feelings of heaviness, swelling, tiredness, and aching in the lower extremities). Even though the chronic venous insufficiency had existed for an average of fifteen years, a relatively short course of the drug caused considerable, and significant, improvements in a number of signs and symptoms of the disease.