Why does peptic ulcer cause black stools?

Digested blood can produce stool that looks black, sticky or tar-like and may have a strong odour. Black Stools is a very common presentation of Peptic Ulcer, but black stool can also follow iron supplements or certain foods and medicines. A clinician needs to distinguish these possibilities, especially if the stool is new or accompanied by symptoms of blood loss.

Contact urgent medical services or seek same-day medical assessment for black, tarry stool unless a clinician has already explained a harmless cause. Do not take anti-inflammatory pain medicines such as ibuprofen or naproxen for suspected ulcer bleeding unless a clinician tells you to. If possible, note the stool appearance, any vomiting, abdominal pain, dizziness and medicines you have used, but do not delay getting help to collect this information.

Call emergency services immediately if black stools occur with vomiting blood or material like coffee grounds, fainting, confusion, severe weakness, cold clammy skin, severe abdominal pain, or trouble breathing. These symptoms can occur with significant bleeding or shock. Even when you feel otherwise well, a new black tarry stool warrants urgent professional advice.

Ask what may have caused the bleeding, whether any medicines need to change, how the ulcer will be investigated or treated, and which symptoms should prompt immediate return. Tell the clinical team about aspirin, anti-inflammatory medicines, blood-thinning treatment, iron products and previous ulcers.