If my stool is black, what should I do?

Melaena, also called tarry stools, is often sticky, very dark, and unusually strong-smelling because blood has been digested as it moves through the gut. It may 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 appearance alone cannot safely identify the cause.

Tell a clinician about pain, indigestion, vomiting, dizziness, weakness, and any medicine that can irritate the stomach or affect bleeding.

Contact urgent medical services for advice, especially if the stool is tarry, the change is new, or you feel unwell. Do not take additional anti-inflammatory painkillers unless a clinician says they are suitable. Keep a list of medicines and supplements, and mention iron or bismuth use. Do not delay assessment simply because the next stool looks lighter.

Go to emergency care for fainting, severe dizziness, confusion, cold or clammy skin, rapid heartbeat, vomiting blood or material like coffee grounds, severe abdominal pain, or repeated black stools. These can signal significant blood loss and need immediate assessment.

Ask whether the stool appearance suggests melaena, which medicines should be paused or avoided, whether you need blood tests or a camera examination, and how to test for Helicobacter Pylori Infection.