Black stool and diarrhea: what to know

True melaena is often black, shiny, sticky, and unusually strong-smelling because blood has been digested before leaving the body. Diarrhea can speed the movement of gut contents and may occur with infection or irritation, but it does not explain away tarry stool. Iron tablets, bismuth-containing remedies, and very dark foods may produce a dark stool without bleeding. A clinician may ask when the change began, how many bowel movements you have had, what you ate, and which medicines you take. Possible causes of upper digestive bleeding include gastritis, Helicobacter Pylori Infection, and Peptic Ulcer.

Do not take anti-diarrhea medicine if you have black, tarry stool until a clinician has advised you. Sip oral fluids regularly, especially if stools are frequent, and keep a note or photo of the stool if this can be done privately. Avoid alcohol and non-steroidal anti-inflammatory painkillers such as ibuprofen unless a clinician has specifically told you to use them. Arrange urgent medical advice today if the stool is tar-like, recurs, or began without an obvious food or medicine explanation.

Seek emergency care for faintness, confusion, marked weakness, a fast or pounding heartbeat, vomiting blood or material like coffee grounds, severe abdominal pain, or trouble staying awake. Black stool accompanied by ongoing diarrhea can cause fluid loss, and bleeding can worsen without warning. Children, older adults, pregnant people, and anyone taking a blood thinner should seek advice particularly promptly.

Ask whether the stool looks like melaena, whether your medicines could be contributing, and whether you need blood tests or stool testing. Tell the clinician about iron, bismuth, aspirin, anti-inflammatory medicines, alcohol use, recent travel, and any previous ulcer or stomach problems. Ask which fluids are suitable and which symptoms should send you directly to emergency care.