Hidrosmin, a synthetic bioflavonoid, is a phlebotonic (capillary stabilising agent). It is marketed under the brand name Venosmil among others. Venosmil is a medicinal product indicated for: short-term (2-3 months) relief from oedema and symptoms related to chronic venous insufficiency in adults. Although the mechanism of action of hidrosmin has not been fully elucidated, it could be related toinhibition of the degradation of catecholamines, specifically inhibition of catechol-O-methyltransferase. Although the exact mechanism of action is unknown, hidrosmin has four main pharmacological actions: 1.It reduces the capillary permeability induced by various agents such as histamine, bradykinin, etc. and reduces the capillary fragility induced by a deficiency diet. 2.It increases the deformability of red blood cells and the viscosity of the blood. 3.It induces the contraction of smooth muscle in the vein wall in a gradual and sustained manner. 4.It produces dilation of the lymphatic collectors and increases the rate of lymphatic conduction, thereby improving lymphatic flow. The efficacy of Venosmil was evaluated in two clinical trials in a total of 70 patients with acute and chronic venous disease, who were treated with 200 mg hidrosmin orally three times per day and/or 2 g hidrosmin topically (gel) two or three times per day for one and two months Hidrosmin was effective at reducing oedema, ulcers and varicose eczema. Venosmil therefore possesses intrinsic activity against the consequences of venous stasis secondary to varicose dilation of the veins in the lower limbs, producing an improvement in the clinical symptoms of peripheral venous insufficiency (pain, heaviness, oedema, etc.) that is significantly different to that produced by placebo.