Sclerotherapy is the injection under ultrasound guidance of a tiny amount of a special solution inside the abnormal damaged vein that causes it to gradually seal and eliminates blood flow. Normal veins will take over the flow of blood in the area, the pressure in the veins will be reduced and the blood circulation in the leg will improve. There are different kinds of solutions in different concentrations used for sclerotherapy. The pros and cons of the various solutions are best discussed with your sclerotherapist.