Hydroxyethylrutosides is a standardised mixture of semisynthetic flavonoids, mainly mono-, di-, tri-, and tetrahydroxyethylrutosides, which acts primarily on the microvascular endothelium to reduce hyperpermeability and oedema. In patients with chronic venous insufficiency or diabetes, hydroxyethylrutosides improves microvascular perfusion and microcirculation, and reduces erythrocyte aggregation. The preparation also has a possible protective effect on the vascular endothelium. In short to medium term placebo-controlled studies (up to 6 months) hydroxyethylrutosides therapy improved signs and symptoms of chronic venous insufficiency, including venous insufficiency associated with pregnancy and lymphoedema, and was well tolerated. However, the long term effects of hydroxyethylrutosides administration have yet to be demonstrated. The preparation also alleviated symptoms in patients with severe haemorrhoids, although there were no corresponding objective improvements. Hydroxyethylrutosides administration has been associated with reductions in retinal vascular permeability in patients with diabetic retinopathy but has no apparent effect on signs of retinal haemorrhage, although a reduction in oedema and haemorrhage has been reported in other patients receiving oral hydroxyethylrutosides in the acute phase of central retinal vein occlusion. There are only limited effective pharmacological treatment options for patients with chronic venous insufficiency or lymphoedema, and hydroxyethylrutosides clearly improves signs and symptoms of these disorders. While its role in diabetic retinopathy and haemorrhoids requires some clarification, hydroxyethylrutosides therapy shows promise as a useful additional option for the management of oedema and other symptoms of chronic venous insufficiency.