The blood turns black as it travels through your digestive system before coming out in your poop. Melena can be a sign of a serious medical condition and requires prompt evaluation by a healthcare provider Hematochezia and melena are two terms that describe different ways blood can appear in your stool
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Hematochezia is bright red blood that generally starts lower in the digestive tract
Melena generally starts much higher up in the digestive tract and results in black, tarry stools.
Melena refers to black, tarry, sticky stools and usually results from upper gastrointestinal bleeding The source of bleeding can come from damage to the lining of the gi tract, breakage of swollen blood vessels, or other conditions that prolong bleeding such as hemophilia. See a healthcare provider when melena is present, as blood in the stool is never normal. 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. Possible causes, signs and symptoms, standard treatment options and means of care and support. Symptoms of gi bleeding can be easy to see, called overt, or not so obvious, known as occult Symptoms depend on the rate of bleeding as well as the location of the bleed, which can be anywhere on the gi tract, from where it starts — the mouth — to where it ends — the anus
Overt bleeding might show up as:
Learn about common causes such as ulcers, gastritis, esophageal varices, stomach cancer, and medications, plus symptoms, risks, and when medical care is needed Melena is more likely when bleeding comes from the esophagus, stomach, or small intestine The black color of melena is caused by blood that has been exposed for several hours to stomach acid and enzymes and to bacteria that normally reside in the large intestine.
