Melena

Melena
Other namesMelaena, melæna
Pronunciation
SpecialtyGeneral surgery, gastroenterology
SymptomsDark blood in stool
Causes

Melena is a form of blood in stool which refers to the dark black, tarry feces that are commonly associated with upper gastrointestinal bleeding.[1] The black color and characteristic strong odor are caused by hemoglobin in the blood being altered by digestive enzymes and intestinal bacteria.[2]

Iron supplements may cause a grayish-black stool that should be distinguished from melena,[3] as should black coloration caused by a number of medications, such as bismuth subsalicylate (the active ingredient in Pepto-Bismol), or by foods such as beetroot, black liquorice, or blueberries.[4]

  1. ^ MedlinePlus Encyclopedia: Bloody or tarry stools, retrieved 19 July 2010.
  2. ^ Walker, Brian; Colledge, Nicki; Ralston, Stuart; Penman, Ian, eds. (2014). Davidson's Principles and Practice of Medicine (22nd ed.). Edinburgh: Churchill Livingstone. p. 854. ISBN 978-0-7020-5103-6.
  3. ^ Navarra, Tova (2004). The Encyclopædia of Vitamins, Minerals, and Supplements. Infobase Publishing. ISBN 9781438121031. Iron supplements cause a grayish-black stool that should be distinguished from the black, tarlike stool that occurs from bleeding ulcer.
  4. ^ Dugdale, David (2009-11-01). "Bloody or tarry stools". National Institutes of Health. Retrieved 2009-11-30.