Daflon 500 mg consists of 450 mg diosmin and 50 mg flavonoid expressed as hesperidin. The authors describe its effects on the microcirculation in chronic venous insufficiency: improvement of venous tone, inhibition of prostaglandin synthesis, protection against free radicals, activation of the complement system, and increased lymphatic drainage. The authors summarize studies of its therapeutic efficacy in reducing venous capacitance, distensibility, and emptying time; reducing capillary permeability; and increasing capillary resistance.