What should you know about passing black, tarry stools?

Melena is stool that is black, sticky, and unusually foul-smelling because blood has been digested as it moves through the upper gut. It can occur with a peptic ulcer, gastritis, or Helicobacter pylori infection. Iron tablets, bismuth-containing medicines, and some dark foods can also change stool colour, but they do not reliably explain a tar-like texture or weakness. The appearance and your other symptoms help a clinician judge the cause.

Contact a medical service promptly, especially if the stool is new or repeated. Note when it began, its texture, and any medicines such as anti-inflammatory painkillers, blood thinners, iron, or bismuth. Do not take extra anti-inflammatory painkillers or alcohol while waiting for advice. A clinician may check your circulation, blood count, medicines, and digestive tract; do not drive yourself if you feel faint.

Go to an emergency department now for black tarry stool with vomiting blood or material like coffee grounds, fainting, confusion, severe weakness, shortness of breath, rapid heartbeat, clammy skin, or severe abdominal pain. These features can indicate significant blood loss. Even without them, new tarry stool deserves prompt assessment rather than watchful waiting.

Ask whether your medicines could contribute, whether you need blood tests or an examination of the digestive tract, and which warning signs should send you back for urgent care.