Black, Tarry Stools (Melena): Causes & When to See a Doctor
Black, tarry, sticky stools — known medically as melena — can be an important warning sign, because they often indicate bleeding from the upper part of the digestive tract (the stomach or food pipe). While some harmless things, such as iron tablets, can darken the stool, true black tarry stools should be assessed promptly.
This page explains what black stools can mean, how to tell them apart from harmless causes, and when to seek care.
What do black stools mean?
When blood comes from higher up in the digestive tract — the stomach or food pipe — it is partly digested on its way through, turning the stool black, sticky and tarry with a distinctive smell. This is different from the bright-red blood of lower-bowel bleeding. Because upper-GI bleeding can be significant, melena is taken seriously.
Not all dark stools are melena: iron supplements, certain medicines and some foods can darken stools harmlessly. The combination of black, tarry, sticky stools — especially with feeling unwell, dizzy or with a fast pulse — is what points to bleeding.
Common causes
- Peptic ulcers in the stomach or duodenum
- Inflammation of the stomach lining (gastritis)
- Bleeding from the food pipe (for example from severe reflux)
- Harmless darkening from iron tablets or certain foods (not true melena)
Less common causes
- Stomach (gastric) cancer
- Bleeding from enlarged veins in the food pipe (varices)
- Esophageal cancer
- Bleeding from a GIST or other tumour
When should you seek medical attention?
- Genuinely black, tarry, sticky stools — seek prompt assessment
- Black stools with vomiting blood or 'coffee-ground' vomit — seek urgent care
- Feeling faint, dizzy, short of breath or having a fast heartbeat
- Black stools with abdominal pain, weight loss or known ulcers
How is the cause diagnosed?
- Urgent assessment and blood tests, including for anaemia
- Upper GI endoscopy — the key test, which can also treat the bleeding
- Tests for Helicobacter pylori infection
- CT or other imaging in selected cases
How black stools are treated
Treatment is directed at the cause and the bleeding. Many causes of upper-GI bleeding, such as ulcers, are diagnosed and treated during the same endoscopy, alongside acid-reducing medication and treatment of any Helicobacter infection. Where a more serious cause such as a tumour is found, it is treated according to its type and stage within a multidisciplinary team.
The priority is prompt assessment, because significant upper-GI bleeding needs timely care.
When surgery may be needed
Most upper-GI bleeding is controlled endoscopically and managed medically, without surgery. Surgery becomes relevant for bleeding that cannot be controlled by other means, and for underlying conditions that need an operation — most importantly, stomach or esophageal cancer, where surgery is a key part of curative treatment.
When to consult a GI surgeon in Lucknow
If you have any of the warning signs above, or a symptom that is persistent, worsening or worrying you, it is worth seeking a specialist opinion. Dr Sandeep Kumar Verma — Director of GI Surgery, GI Oncology & Bariatric Surgery at Medanta, Lucknow — offers clear, unhurried assessment to find the cause and guide you on the right next step.
Black Stools: frequently asked questions
Are black stools always a sign of bleeding?
No. Iron tablets, certain medicines and some foods can darken stools harmlessly. However, genuinely black, tarry, sticky stools can indicate bleeding from the stomach or food pipe and should be assessed promptly — particularly if you also feel unwell, dizzy or have vomited blood.
What is the difference between black stools and red blood in stool?
Black, tarry stools (melena) usually mean bleeding from the upper digestive tract — the stomach or food pipe — where blood is partly digested. Bright-red blood usually means bleeding lower down, in the colon, rectum or anus. The colour helps the doctor decide where to look first.
Concerned about black stools?
Don't wait and worry. Book a consultation with Dr Sandeep Kumar Verma for a clear assessment and honest advice on the next step.