In sclerocompression therapy, fluid is injected into a few places in the varicose vein. Veins are then flattened (compression) by putting a cotton ball and tight stocking around them. The injected fluid causes the walls of the veins to stick together and shrivel in a few weeks. The blood then flows through other veins. Most people do not experience this treatment as painful and numbing is therefore not necessary. Usually one leg at a time is treated.