Sclerotherapy is a simple procedure which involves injecting a solution into the vein using a micro-needle, thereby causing the vein to collapse and fade from view. It is a virtually painless treatment which has been shown to be the most successful treatment available today for these tiny blood vessels. The dilute irritant solution injected into the vein damages the vessel lining causing it to close off. The body treats this as damaged tissue which is slowly absorbed over about three months. The injections are almost painless. They look worse to begin with and large vessels may go black. Fading starts after three weeks and it will be three months before the main benefit is seen and improvement continues for a year.