Sclerotherapy uses an injection of a special chemical (sclerosant) substance, into a varicose vein, to damage and scar the inside lining of the vein. This then causes the vein to close. During this procedure, the affected leg is elevated to drain blood, and the sclerosant is injected into the varicose vein. The procedure is done in a doctor’s office or clinic, and takes approximately 5 to 30 minutes, depending on how many varicose veins are treated, as well as how big they are. After the injection of sclerosant is given, pressure is applied over the veins to prevent blood to return, when you stand up. You may need to wear compression stockings for several days or weeks to maintain the pressure. The sclerotherapy injection may be painful, and the chemical (sclerosant) that is injected can cause a feeling of burning or cramping for a few minutes, in the area where the shot was given. You may require multiple sessions depending on the extent of the varicose veins, and the type of sclerosant used.