WINSTROL belongs to the class ‘anabolic steroids’ used in the treatment of hereditary angioedema. It is a rare genetic condition characterized by recurrent episodes of severe swelling (angioedema). Most common areas of the body to develop swelling are the limbs, face, intestinal tract, and airway. Minor trauma or stress may trigger an attack, but swelling often occurs without a known trigger.Stazol contains stanozolol, a synthetic anabolic steroid (a man-made steroid, similar to the a naturally occurring steroid testosterone). Stazol works by reducing the release of a chemical called bradykinin (peptide, that promotes inflammation), which is responsible for breaking and leakage of blood vessels. This damage to blood vessels leads to sudden accumulation of fluids below the skin causing swelling (edema) as well as redness. By this way Stazol blocks the action of bradykinin and treats angioedema.