Sclerotherapy is a safe and well established treatment for thread veins on the legs. It is aimed at reducing and improving the appearance of unsightly thread veins often referred to as “spider veins” by injecting with a very tiny needle, very superficially into the veins with a solution called (fibrovein). The injection causes the lining of the vein to swell and become sticky. Compression is then applied to close the veins. Over a period of time the vein will heal closed and fade away.