Black tarry stool causes: what to know

Melaena is stool that is black, sticky, and often unusually strong-smelling because blood has been digested as it moves through the stomach or small intestine. Possible sources include gastritis, a peptic ulcer, or irritation linked with Helicobacter pylori infection. Iron tablets and bismuth-containing stomach remedies may darken stool without causing bleeding, but colour alone cannot safely distinguish the causes.

Think back to recent medicines, supplements, and foods, and note when the change began, how often it happened, and whether the stool was sticky or loose. Do not stop a prescribed medicine without advice. Arrange prompt medical assessment if the colour is unexplained or returns; a clinician may review your medicines, examine you, and decide whether blood tests or digestive-tract testing is needed.

Seek emergency help for black tarry stool with vomiting blood or material resembling coffee grounds, fainting, marked weakness, confusion, shortness of breath, severe abdominal pain, or cold clammy skin. These signs can accompany significant gastrointestinal bleeding. Do not drive yourself if you feel faint; ask someone to help or contact local emergency services.

Ask whether your medicines or supplements could explain the colour, whether testing for Helicobacter pylori is appropriate, and which symptoms should trigger immediate reassessment. Tell the clinician about pain, indigestion, dizziness, vomiting, alcohol use, and any medicine that can irritate the stomach.