Anticoagulant activity refers to the ability of certain substances to prevent blood from clotting. This is important in medical treatments for conditions such as heart disease, stroke, and deep vein thrombosis, where excessive blood clotting can be harmful. Anticoagulants work by interfering with the body's natural blood clotting process, primarily by inhibiting the activity of specific enzymes or proteins involved in clot formation. Common examples of anticoagulants include heparin, warfarin, and newer oral agents such as dabigatran and rivaroxaban. Managing anticoagulant therapy requires close monitoring to ensure that blood does not become too thin, leading to excessive bleeding.