Active topical hemostatic agents have biological activity and directly participate at the end of coagulation cascade to induce a clot at the site of bleeding. Active agents used in surgery include thrombin and combination products containing thrombin.Thrombin converts fibrinogen (present in patient's blood) into an insoluble fibrin clot. Additionally, thrombin promotes clot formation by activating platelets, leading to fibrin binding and aggregation of these cells. ReliStat is a