Proven safe & effective for people on blood thinners! Stops bleeding instantly. 4 single use applications. WoundSeal Powder is specially developed to stop bleeding for people on blood thinners because it doesn't rely on the normal clotting factors in your blood. It forms an instant seal (or scab) over the wound in seconds. The seal is safe to leave in place until it falls off naturally and the wound heals. Now you have confidence to know you can control bleeding wherever you are. CE listed.