Black stool, whether solid or liquid, is usually caused by bleeding in the stomach or upper intestines. This is because the blood comes into contact with digestive juices and turns black. Common causes include: Some foods and medicines can also turn your pet’s stool black, but they do not have any short-term negative effects on your pet, such as grilled liver, boiled animal blood, blood tonics that contain iron, activated charcoal, etc., or even ingesting your own blood from mouth ulcers or nosebleeds. If you notice other abnormalities, such as pale mucous membranes, lethargy, vomiting, or loss of appetite, you should take your pet to see a veterinarian for an urgent diagnosis, as severe anemia may occur. Information from: Dr. Kuncharee…