Dark-colored stools may be seen in platelet function disorders, iron deficiency anemia, cirrhosis, colorectal cancer, disseminated intravascular coagulation, peptic ulcer, or stomach cancer. Liver disease may include a yellow tone to the skin and whites of eyes (jaundice) and brownish urine.
Black or tarry stools (Melena)
The passage of black, tarry and foul-smelling stools; can be an indication of digested blood in the stool. Other causes are, iron deficiency anemia, cirrhosis, colorectal cancer, disseminated intravascular coagulation, peptic ulcer, or stomach cancer. In advanced cirrhosis (liver disease), the abdomen becomes distended with fluid and ruptured blood vessels in the stomach and esophagus cause bleeding. The person may vomit blood or pass black stools. Very dark stools, for example, may indicate an ulcerative lesion in the higher digestive tract.
Note: The ingestion of black licorice, lead, iron pills, Pepto-Bismol, or blueberries can all cause black stools or false melena. Stools should be tested for the presence of hidden blood.
Blood in the stool (Hematochezia) - the passage of red, or maroon- colored stools. Red or "frank" blood in the stool could be caused by hemorrhoids. Bloody stools can also be seen in amebiasis, anal fissures, or colorectal cancer. Bright red bleeding with bowel movements may be due to hemorrhoids; however, other conditions such as colonic polyps or tumors, diverticulosis, and abnormal small vessels called AVMs also may cause bleeding. Unusually, the bleeding is coming from the upper intestine or stomach. Bleeding such as you describe usually is evaluated by colonoscopy. Blood, as seen in the stool, can originate anywhere along the intestinal tract. A black stool usually means that the blood is coming from the upper part of the GI tract. At least 6 Tablespoons (or 200 milliliters) of blood must have been lost in order to cause passage of melena. Maroon-colored stools or bright red blood usually suggest that the blood is coming from large bowel or rectum. However, sometimes can be caused by massive upper GI tract bleeding. Some upper GI causes of bloody stools can also cause vomiting blood such as in peptic ulcer disease. The color of the stool can suggest the location of the bleeding however this is not reliable. A definitive diagnosis will require radiographic and/or endoscopic investigation.
Black color -
- bleeding ulcer
- gastritis
- esophageal varices
- a tear in the esophagus from violent vomiting
Maroon color -
- all the causes of black color stool
- diverticular bleeding
- vascular malformation
- intestinal infection (such as bacterial enterocolitis)
- inflammatory bowel disease
- tumor
- colon polyps or colon cancer
Bright red color -
- all the causes of black or maroon color stool
- hemorrhoids
- anal fissures ("cracks" in the anal area)
Gray stools
Gray stools pale stools, putty or clay colored stools may be seen in hepatitis, gallbladder disorders, or malabsorption conditions. Bile salts in the stool excreted by the liver give it a normal brown color. Obstruction to bile flow out of the liver (you may see the word "cholestasis"), or liver infections like viral hepatitis (A, B, C, etc.), may produce clay colored stools. Possible causes for clay colored stool result from problems in the biliary system (the drainage system of the gallbladder, liver, and pancreas): Malabsorption problems can cause undigested fat in the stool (steatorrhea) which is characterized by foul smelling, light yellow to gray, greasy or frothy stools. This may also be caused by low bile output.
Orange Stool
Artificial orange or yellow colorings, or other artificial colorings can product orange stools. Where on earth did you ever get the idea that bright yelloe stool indicates excessive bile involvement ? . Nothing coud be further from the truth. It's the opposite. It is the addition of bile into the intestinal tract as part of the digestive process that actually turns the stool brown. Orange stools may be due to certain medications. Beta-carotene (a form of vitamin A) may cause orange stools as a side effect so check any sources of vitamins or supplements, as well as intake of foods high in beta-carotene (carrots, sweet potatoes, etc.). Another possibility is if the stool is more pale-orange, it might indicate lack of bile salt (which gives stool a brownish color). Other sources are antacids containing aluminum hydroxide, barium from recent barium enema test, and hepatitis. Consider checking some baseline liver tests to evaluate proper liver function.
Green Stool
Stool starts out green , then turns bright yellow as it goes through the digestive tract. It is bile and bacteria that finally turn it brown. Yellow or green stools can indicate stool is passing through the digestive tract too rapidly not giving it a chance to change colour. Bright yellow stools can also indicate not enough bile / bilary obstruction. Green stools may be bacteria, or a green or blue food eaten. Green, blue, or yellow artificial colorings too.
