Collagen hemostat is an absorbable topical hemostatic agent prepared from purified bovine corium collagen and shredded into fibrils. In contact with a bleeding surface, collagen hemostat attracts platelets which adhere to its fibrils and undergo the release phenomenon. This triggers aggregation of the platelets into thrombi in the interstices of the fibrous mass, initiating the formation of a physiologic platelet plug.