What should you know about partial black stool?

Black stool that is sticky, tar-like or unusually foul-smelling may contain digested blood from the upper digestive tract. A small dark area can also follow iron supplements, bismuth-containing remedies or strongly coloured foods. These explanations cannot be separated reliably by appearance alone.

Bleeding from gastritis, Helicobacter Pylori Infection or a Peptic Ulcer can present with black stool. Notice whether the whole bowel movement is dark, whether the change repeats, and whether you have upper abdominal discomfort, weakness, dizziness or vomiting.

If the dark stool is new or returns, contact a clinician promptly and describe its texture, timing and any medicines or supplements. Do not stop a prescribed medicine without advice. Keep a note of foods, iron or bismuth products and bowel changes; a clinician may examine you and arrange stool or blood tests.

Avoid taking anti-inflammatory pain medicines such as ibuprofen or naproxen until a clinician has considered bleeding risk, unless they have specifically advised you to use them. Drink normally, but do not delay assessment to watch the colour for several days if you feel unwell.

Seek emergency care now for black tarry stool with fainting, marked dizziness, confusion, unusual weakness, rapid breathing, severe abdominal pain, vomiting blood or vomit that looks like coffee grounds. Urgent assessment is also needed if black stools are repeated or you take a blood thinner.

A single dark patch after a clearly identified food or product may be less concerning, but arrange medical advice if the change persists, has no clear explanation or occurs with tiredness, pallor or abdominal symptoms.

Ask: Could my medicines, supplements or food explain this colour? Does the texture suggest digested blood? Do I need tests for gastritis, Helicobacter Pylori Infection or a Peptic Ulcer? Which pain relievers should I avoid while this is being assessed?