What should you know about what passing black stool means?

Black stool is sometimes caused by iron, bismuth, or dark foods. Stool that is shiny, sticky, tar-like, and strongly unpleasant is more concerning because digested blood can turn black as it travels through the upper digestive tract. Gastritis, Helicobacter pylori infection, and peptic ulcer are possible causes of upper-gut bleeding. Colour alone cannot establish the cause, so describe the appearance and any accompanying symptoms.

Seek prompt medical advice for new black stool, particularly if it repeats. Make a list of medicines and supplements, including iron, blood thinners, aspirin, and anti-inflammatory painkillers. Do not change prescribed treatment without guidance. Keep hydrated if you are alert and able to drink, but do not delay care to monitor the next bowel movement if you feel unwell.

Go to emergency care for black stool with fainting, marked weakness, dizziness, rapid heartbeat, clammy skin, breathlessness, abdominal pain, or vomiting blood or coffee-ground material. These symptoms can accompany significant bleeding. Seek help immediately if you become confused or difficult to wake.

Ask whether the stool pattern could be medication-related, whether you need blood tests, and how the clinician will check for bleeding or an ulcer.