When pets are exposed to and ingest the modern rat poisons (warfarin, coumarin and derivatives), they lose the ability to clot blood for 4-6 weeks. The coagulopathy (clotting disorder) and resultant blood loss requires close monitoring and vitamin K capsule administered daily for 6 weeks to be absolutely safe. Any signs of bleeding, petechiations (small purple spots) of oral mucosa, purpuric hemorrhage of abdomen (big purple blotches), epistaxis (nose bleed), hematuria (bleeding in urine), or melena (bloody stool) or dyspnea (difficulty breathing) should be attended to by a veterinarian immediately. Periodic blood checks (PCV and hematocrit) are recommended to confirm that the Vitamin K antidote is working effectively at counteracting the poison.