Sclerotherapy has been the same since the appearance of the hypodermic needle, what has changed in time have been the schlerotherapy liquids that have gone from iodine and alcohol to mercury bichloride passing through different compounds of sodium and hypertonic glucose solutions or soapy solutions with oily acids of different origins.

The current schlerotherapy agents are effective and more innocuous such as hydroxipolyetoxydodecane (etoxisclerol), discovered by Henschelt in 1966.

The requirements for a sclerosing agent must be:

• That it be a stable product, in order to ensure a uniform action.
• Easy to use: preferably of a clear color in order to reveal aspirated blood and to have some physical-chemical conditions that permit a rapid and effective technique
• That it be light: if it thickens, it obstructs the needles
• That it be painless: an important condition
• That it be innocuous: its action must be limited to cause an aseptic chemical inflammation, localized in the far parts of the injected point, the consequence of which is the destruction of the venous endothelium y the introduction of small thrombus firmly adhering to the endovein without involving the rest of the caps of the venous wall. That is to say, this might provoke an endophlebitis without periophlebitis.
• Non-clotting, since it is a schlerosing agent, just put in contact with blood, it coagulates, it tends to obstruct the tip of the syringe and causes to bring about the injection in a rapid way, by increasing the risk of provoking an extravasation.
• Active and effective: in order to permit ambulatory forms of treatment
• Atoxic and hypoallergenic: administrated in proper quantities.
• Not provoke a secondary thrombosis
• Having a limited and controllable action.