Sclerotherapy (also called scleropathy) is a medical intervention to close veins that have become defective and do not function properly anymore. It is used in varicose veins in the legs, in the gullet or in the anus (hemorrhoids), for example. In this procedure, a substance is injected into the vessel affected that causes a local inflammation of the vessel wall. The walls then get stuck to each other, which in turn closes the vessel.