What should you know about pure black stool?

Contact a clinician the same day, even if you otherwise feel well, so they can decide whether you need urgent examination or testing.

Blood exposed to digestive juices can turn stool black and make it look shiny, sticky, or unusually foul-smelling. This pattern is often called melaena. Bleeding can arise from the oesophagus, stomach, or first part of the small bowel.

Gastritis and peptic ulcers can bleed into the upper digestive tract. Helicobacter pylori infection can contribute to stomach inflammation or ulcers. Iron supplements and medicines containing bismuth may darken stool too, but do not assume medication is the explanation for a new tar-like stool.

Arrange prompt medical advice and mention when the black stool began, whether it was sticky or tar-like, and any stomach pain, nausea, vomiting, weakness, or recent bowel changes. Take a list of all prescription medicines, over-the-counter pain relievers, supplements, and herbal products.

Avoid starting or increasing anti-inflammatory pain medicines unless a clinician tells you to, because some can irritate the stomach or worsen bleeding. Do not stop a prescribed blood-thinning medicine on your own; seek urgent advice about the next dose instead.

Seek emergency care now if black stool occurs with fainting, dizziness, confusion, marked weakness, shortness of breath, chest discomfort, vomiting blood, vomit that resembles coffee grounds, or severe abdominal pain. These symptoms can accompany significant blood loss or another urgent illness.

If the stool is black but you have none of these warning signs, it still deserves same-day clinical advice, particularly when it is new, repeated, or unexplained.

Ask whether the appearance suggests bleeding, which medicines or supplements could be involved, and whether you need blood tests, a stool test, or a camera examination of the upper digestive tract. Also ask what symptoms should make you seek emergency care while waiting for results.