Sclerotherapy treats spider veins appearing on the legs. This procedure involves a series of micro-injections that instills a solution into the tiny capillaries using a very tiny needle so fine that you can barely feel it. This solution acts to eliminate the blood vessel by trying to collapse it and break it down. It does this without harming circulation or other blood vessels. Those with only a few tiny veins may need only one treatment. Usually the vessels disappear over a period of two weeks to two months. If the veins are larger, each will likely need two to three treatments to totally resolve. Extremely severe cases require about six treatments.