Sclerotherapy is a minimally invasive procedure done by a physician to treat uncomplicated reticular veins (very small spider veins and uncomplicated small varicose veins). The treatment involves the injection of a solution into the affected veins. It works by damaging the cells lining the inside of the blood vessels causing blood platelets to attach to the lining of the vessels. Eventually, cellular debris and platelets cause the blood vessels to clot. Over time, the clotted vein will be replaced with tissue. For best results, it is recommended that you plan for three sclerotherapy treatments spaced 4 to 6 weeks apart.