Sclerotherapy (sklair-oh-THAIR-uh-pee) is a procedure in which varicose or spider veins are injected with a solution to encourage their collapse and disappearance. No anesthesia is required, other than that which may be included in the sclerosing solution. Pain is typically minor and can be minimized with the use of the proper needle and solution. Experts advise using the smallest needle possible and replacing it with a fresh needle after multiple injections. Angled needles that are silicone-coated typically cause the least discomfort. The choice of sclerosing solution is another important consideration. Those which contain a substance called hypertonic saline (hy-puhr-TAWN-ihk SAY-leen) are more likely to cause burning or cramping after they're injected than so-called detergent-based solutions. If a stinging sensation does occur, it can be reduced by pressing down on the area after injection or rubbing it with alcohol. Following treatment, it's not uncommon to feel a temporary, mild aching in the legs. This can be eased by wearing medical grade compression stockings and by walking around immediately after the procedure.