What should you know about blood in stool is called melena?

Blood that remains in the stomach or small intestine can be altered by digestive juices, making the stool dark rather than bright red. Melena may have a strong, unusual smell and a sticky or tar-like texture. Possible sources include an ulcer, inflammation, irritation, or another problem in the upper digestive tract. Medicines such as blood thinners and anti-inflammatory pain medicines can increase concern when bleeding is suspected. Iron tablets and some dark foods can also change stool colour, but they do not create the typical tar-like appearance of melena. A clinician may need to examine you and arrange blood tests or other investigations to find the source.

Melena describes a sign, not a diagnosis. It does not by itself identify the cause, and a person may have bleeding without severe pain.

Arrange urgent medical advice if your stool is black and tar-like, especially if this is new or unexplained. Do not wait for the colour to clear before getting advice. Note when it started, how often it has happened, whether the stool was sticky, and whether you have taken iron, bismuth, anti-inflammatory pain medicines, or blood thinners. Take or photograph the medicine packaging if helpful. Do not stop a prescribed blood thinner without medical advice, and avoid taking extra anti-inflammatory pain medicine while waiting to be assessed.

Seek emergency care now for black stool with dizziness, fainting, confusion, unusual weakness, shortness of breath, a fast heartbeat, pale or clammy skin, vomiting blood, or severe abdominal pain. These symptoms can indicate significant blood loss or reduced circulation. If you feel faint, do not drive yourself; ask someone to help or call local emergency services. Even without these warning signs, new melena warrants prompt assessment because internal bleeding can worsen while symptoms seem limited.

Ask what may be causing the dark stool and whether you need tests to locate bleeding. Tell the clinician about stomach pain, vomiting, bowel habit changes, previous ulcers, liver disease, and every medicine or supplement you use. You can also ask which medicines to avoid, what warning symptoms should send you back urgently, and how the suspected cause will be treated. If a bowel polyp is found, ask whether removal is appropriate and how follow-up will be arranged.