Loose stool with black color: what it can mean

Loose black stool can result from food or medicine, but tarry stool may signal bleeding in the upper digestive tract and needs prompt medical assessment. Color alone cannot identify the cause. Note whether the stool is truly black, sticky, shiny, or unusually foul-smelling, and whether you have other symptoms.

Iron tablets, bismuth-containing stomach remedies, activated charcoal, and deeply pigmented foods can darken stool without causing bleeding. These changes are often more uniform in color and may settle after the trigger is no longer being used. Do not stop a prescribed medicine without medical advice.

Black, tar-like stool can occur when blood is digested as it travels from the stomach or the first part of the small intestine. Possible sources include irritation of the stomach lining, a Helicobacter pylori infection, or a peptic ulcer. Gastritis can also cause upper-abdominal discomfort and, when bleeding occurs, dark stool.

Diarrhoea can make stool more watery, but it does not explain a tarry black appearance by itself. A clinician may ask about medicines such as aspirin or anti-inflammatory painkillers, alcohol use, previous ulcers, abdominal symptoms, and any vomiting that looks like coffee grounds.

If the stool is black and tarry, contact a healthcare professional promptly, even if you feel otherwise well. Keep a note of when it started, how often it has happened, and any new food, supplement, or medicine. If safe and practical, a photo can help describe the appearance.

Drink small, regular amounts of fluid if you have loose stools, unless a clinician has told you to restrict fluids. Avoid taking anti-inflammatory painkillers such as ibuprofen or naproxen for this problem unless a healthcare professional advises you to use them. Do not use anti-diarrhoeal medicine to delay assessment of black, tarry stool.

Seek emergency care now if black stool occurs with dizziness, fainting, marked weakness, confusion, fast or pounding heartbeat, pale or clammy skin, severe abdominal pain, repeated vomiting, or vomit containing blood or material that resembles coffee grounds. These features can indicate significant bleeding or dehydration.

Arrange prompt medical review for any unexplained black stool, repeated episodes, worsening diarrhoea, fever, or symptoms of anaemia such as unusual tiredness or breathlessness. Children, older adults, pregnant people, and anyone taking blood thinners should seek advice without delay.

You could ask: Could my medicine or supplement explain the color? Does the appearance suggest digested blood? Do I need tests to check for anaemia or a source of bleeding? Should I change any painkiller, blood thinner, or stomach medicine? What symptoms should prompt emergency care?