Setrol Injection 2 ml belongs to the group of medicines called sclerosants or sclerosing agents primarily used in the treatment of varicose veins, large, medium or minor venules and spider veins. Varicose veins are swollen veins that generally appear in the legs and feet. They can be blue or dark purple in colour and have a lumpy, bulging, or twisted appearance. The active component in Setrol Injection 2 ml is sodium tetradecyl sulphate. It works by scarring the vein, prompting blood to reroute through healthier veins. The collapsed vein is reabsorbed into the surrounding tissue and finally fades away.