What should you know about black dark green poop?

Green vegetables, dark-coloured foods, iron supplements, and some medicines can change stool colour. Green stool can also appear when bile moves quickly through the bowel. Black stool is more concerning when it looks sticky, tar-like, or unusually foul-smelling, because digested blood from the stomach or upper intestine can create that appearance. Conditions such as gastritis, Helicobacter Pylori Infection, or a peptic ulcer can be associated with upper digestive bleeding, but colour alone cannot identify the cause.

Think back to recent foods, supplements, and medicines, and note when the colour began. Do not stop a prescribed medicine without advice. If the stool remains black, is tarry, or has no clear food or medicine explanation, arrange prompt medical advice. A clinician may ask about abdominal discomfort, dizziness, vomiting, bowel changes, and medicines that can irritate the stomach. Keep a photograph only if you can do so privately and safely; a description is usually enough.

Seek urgent medical care for black tarry stool with faintness, marked weakness, confusion, shortness of breath, rapid heartbeat, severe abdominal pain, or vomiting blood or material resembling coffee grounds. These symptoms can accompany significant bleeding. Even without those warning signs, repeated unexplained black stools deserve prompt assessment, especially if you take blood-thinning medicine or have a history of ulcers.

Could a food, supplement, or medicine explain this colour? Does the texture suggest digested blood? Do I need tests for anaemia or an upper digestive cause? Which symptoms should prompt emergency care?