An antihemorrhagic (antihæmorrhagic) agent is a substance that promotes hemostasis (stops bleeding). It may also be known as a hemostatic (also spelled hæmostatic) agent. An antihemorrhagic (antihæmorrhagic) agent is a substance that promotes hemostasis (stops bleeding). It may also be known as a hemostatic (also spelled hæmostatic) agent. A styptic (also spelled stiptic) is a specific type of antihemorrhagic agent that works by contracting tissue to seal injured blood vessels. Styptic pencils contain astringents.