Black or very dark, tar-like stool can be harmless in some cases, but it can also be a sign of internal bleeding and needs urgent medical attention if it’s persistent or you feel unwell.

Quick Scoop: What black stool can mean

There are two big buckets of causes:

  1. Not-so-serious (often food or meds)
 * Iron supplements.
 * Medicines with bismuth (like some diarrhea/indigestion meds).
 * Activated charcoal.
 * Dark foods: black licorice, blueberries, blackberries, blood sausage, very dark food colorings.

If this is the reason, your stool is usually dark but not sticky-tarry, and you generally feel otherwise OK.

  1. More serious (possible internal bleeding)
    • Bleeding from the esophagus, stomach, or upper small intestine (e.g., ulcers, gastritis, esophageal varices).
 * Inflammation in the gut (like colitis) or other lesions and growths.

This kind of stool is often described as:

 * Very dark or black.
 * Shiny and **tarry** (like thick oil or tar).
 * With a strong, foul smell.

When blood from high up in the digestive tract gets digested as it moves through, it turns dark and can make your stool look black.

When to worry right now

You should seek urgent medical care (ER or urgent care) if you have black stool and any of these:

  • Dizziness, lightheadedness, or feeling like you might faint.
  • Rapid heartbeat or shortness of breath.
  • Weakness, pale skin, or sweating.
  • Vomiting blood or something that looks like coffee grounds.
  • Strong abdominal pain.

These can be signs of significant internal bleeding and are considered emergencies.

Even if you feel okay, you should contact a doctor soon (within 24 hours) if:

  • Your stool is black/tarry more than once.
  • You can’t clearly link it to a recent dark food or new medication.
  • You are older, have a history of ulcers, liver disease, or are taking NSAIDs (ibuprofen, naproxen) or blood thinners.

Quick self-check (this does NOT replace a doctor)

Ask yourself:

  1. Did I recently eat:
    • Black licorice, blueberries, blackberries, blood sausage, dark food dyes, charcoal-containing foods/supplements?
  1. Did I recently start or increase:
    • Iron supplements.
    • Bismuth meds for diarrhea/indigestion.
    • Activated charcoal products.
  1. What does it look like?
    • Merely dark brown and formed, no bad smell, and I feel fine → more likely diet or meds.
    • Jet black, sticky, shiny, tar-like, very smelly → more concerning for upper GI bleeding.
  1. How do I feel overall?
    • Weak, dizzy, or short of breath, or I look pale → this can be a sign of blood loss and needs urgent care.

If you’re unsure, it’s much safer to get checked than to wait.

What doctors usually do

If you go in, they may:

  • Ask detailed questions about:
    • Recent foods and medications.
    • Pain, nausea, vomiting, weight loss, changes in bowel habits.
  • Do a physical exam and possibly a rectal exam.
  • Order:
    • Blood tests (to look for anemia, infection, clotting issues).
    • Stool tests for hidden blood.
    • Endoscopy (camera down the throat) if they suspect bleeding in the upper gut.

Treatment depends on the cause: stopping a culprit medication, treating ulcers, managing inflammation, or in severe cases, hospital care for bleeding.

Bottom line (and what you should do)

  • Black stool can be from harmless causes like iron, bismuth, or dark foods, but it is also a classic warning sign of upper GI bleeding.
  • If your stool is truly black and tar-like, especially if it happens more than once or you feel unwell, you should not wait to see if it goes away on its own.
  • Because I don’t know your age, medications, or other health issues, the safest advice is:
    • If this is new for you and not clearly from food/iron/bismuth, contact a doctor or urgent care today.
    • If you have any dizziness, weakness, chest pain, or vomiting blood, go to emergency services immediately.

If you tell me your age, medications, recent foods, and other symptoms (pain, nausea, dizziness, etc.), I can help you think through how urgent this might be—but this should always be in addition to getting real-world medical care, not instead of it.

Information gathered from public forums or data available on the internet and portrayed here.