Background: Tranexamic acid is an antifibrinolytic that prevents the activation of plasminogen to plasmin. Plasmin is responsible for the degradation of fibrin clots. This is the mechanism by which tranexamic acid prevents blood clot breakdown and reduces operative bleeding. Functional endoscopic sinus surgery, or FESS, is a widely used surgical technique to treat sinusitis and other diseases of the nose and nasal cavities. Bleeding during FESS can hinder surgical progress and has been associated with an increase in complications.