Blood in the stool or gastrointestinal tract may take various forms or appearances depending on where it is coming from and how brisk the bleeding. There are common medical terms and definitions for blood in the gastrointestinal tract or stool that may not be familiar to the lay public but can be helpful to know if you or a family member experience gastrointestinal bleeding.

Hematemesis is the medical term for vomiting blood. Red hematemesis is vomiting red blood. Coffee ground's hematemesis is vomiting blood altered by stomach juices. Blood in the stomach is quite nauseating usually resulting in vomiting. Vomiting blood is called hematemesis. It can be bright red if occurring briefly after the blood enters the stomach or when the bleeding is brisk. Stomach acid and digestive juices alter any blood that remains in the stomach. If the altered blood is vomited, it usually appears like old coffee grounds, hence the term "coffee grounds like" hematemesis. Blood may originate from the stomach, be swallowed, or regurgitated from the duodenum, the first part of the small intestine just after the stomach.

Melena a medical term for blood in the stool that changes the color of the stool. Melena is derived from term for black, thus for strict purposes melena is stool that is black (and usually tarry and very malodorous) from blood that is partially digested or altered. Blood in the digestive tract is a very potent laxative so it is common that melena takes the form of black diarrheal stool with associated urgency. If blood in the stomach is not vomited completely the altered blood passes into the intestine where it usually triggers diarrhea. However, the diarrhea is usually black, tarry and foul smelling. This is termed melena or melenic stool. Though many doctors mistakenly refer to such stool as melanotic that is an incorrect term. Melanotic refers to containing melanin, the dark skin pigment present in moles and the malignant skin cancer, melanoma. Melena or melenic stools indicate an upper gastrointestinal tract bleed or source of blood because it has been altered by digestive juices only present in the stomach and upper small intestine. Such bleeding usually originates from a site reachable by an upper scope though occasionally the site is beyond the reach of such a gastroscope.

Hematochezia is the medical term for red or marroon blood in the stool or passed rectally. It almost always signifies a lower gastrointestinal hemorrhage or rectal bleeding though in a massive upper GI bleed the blood can pass so quickly that it is not turned into melena but comes out red or marroon. Otherwise, red blood passed rectally usually indicates the source of bleeding is in the lower colon or rectum, or lower GI bleed. Bright red blood on toilet paper or dripping in the toilet bowl is usually from the anus or rectum, most commonly from hemorrhoids or an anal fissure, though can occur with rectal cancer.

Bloody diarrhea, often with mucus, is typical of colitis. Colitis is inflammation of the colon or large intestine from any of a number of causes that may include infection, poor blood flow to the intestine (ischemia) and the chronic inflammatory bowel diseases ulcerative colitis and Crohn's disease.

Yes, that is called occult blood in the stool. It takes about 50-100 ml blood to turn the stool black or melenic. Less than 2 cups of bleeding is therefore not usually visibly detectable and is termed occult blood in the stool. Various chemical tests for occult blood in the stool exist that can be done on evacuated stool or stool obtained by a gloved finger exam by a doctor. Occult blood in the stool is concerning for cancer and necessitates an evaluation for the cause. Ulcers, acid reflux, Celiac disease, polyps, colitis and Crohn's disease, hemorrhoids and aspirin type medication injury to the gastrointestinal tract are all common non-cancer causes of occult blood in the stool.

See your health care provider if you experiencing bleeding from your digestive tract or observe any of the forms of blood in your stool. Use the above guide to accurately describe to your health care provider what you observe and/or to communicate more clearly to them about your symptoms. You will more educated and effective advocate for yourself as well as search more intelligently for the cause, diagnostic options and treatments available if you understand these terms and the possible causes and treatment for the various forms of GI bleeding.