Spider veins on the legs can be treated with an injection method.  The procedure is called sclerotherapy. One of the several kinds of  solutions called sclero skin solution is injected with a very fine needle directly into the blood vessel.

This procedure has been used for spider veins since the 1930’s and before that for larger veins. The solution irritates the lining of the blood vessel causing it to swell, stick together and the blood to thicken. Over a period of weeks the vessel turns into scar tissue that is absorbed essentially becoming barely noticeable or barely visible.  A single blood vessel may have to be injected more than once several weeks or months apart depending on its size.  In any one treatment a number of vessels can be treated.