Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Stool
(feces) is most commonly brown in color, and many people become curious or
concerned when the color of their stool changes. Most stool-to-stool changes in
color have little meaning; however, some changes, particularly if the changes
are consistent from stool-to-stool and not present in only one stool, can be
important.
What causes normal stool color?
The color of stool is normally due to the presence of bile, specifically, the
bilirubin in bile. Bilirubin is formed from
hemoglobin after hemoglobin is
released from red blood cells during their destruction, a part of the normal
process of replacing the red blood cells in blood. The released hemoglobin is
modified chemically and removed from the blood by the
liver. In the liver the
chemically changed hemoglobin (called bilirubin) is attached to other chemicals
and secreted from the cells of the liver into bile. Depending on the
concentration of bilirubin, bile can vary from almost black to light yellow in
color.
Bilirubin travels with bile that is produced by the liver and then transported out of the liver by the bile ducts into the gallbladder, where it is stored until it is released into the intestines. (Bile is an important way for the liver to get rid of waste products such as bilirubin that are formed within the body.) As the bile and bilirubin pass through the intestines they are exposed to bacteria within the intestines. The bacteria can change the chemical nature of bilirubin, and this can change the color of stool.
If stool travels through the intestines at a normal speed, its color is a normal brown. Travel at a more rapid speed can result in chemical changes that may turn the stool green. Thus,
green stool by itself is only a sign of a change of the speed with which stool is traveling and not necessarily a sign of disease. On the other hand, if the entry of bile into the intestines is blocked, for example, by a tumor of the bile ducts or pancreatic cancer, the stool becomes
clay-colored. Clay-colored stool always is a sign of important disease.
Reviewed by Melissa Conrad Stöppler, MD on 3/7/2013
It started with feeling a little run down after working extra hard, perhaps
there was some lightheadedness when he stood too quickly, and then came the
fatigue. The baseball world blamed Ichiro Suzuki's malaise on playing too
much in the World Baseball Classic. During spring training, baseball players are
supposed to lounge and gradually get themselves into shape,
not play like it's the World Series in October. But the baseball world was
wrong. It was discovered in April 2009 that Ichiro was tired because he was
anemic and because
he was bleeding from an ulcer.
The scenario plays out routinely off the playing field too often. A person
feels run down and blames it on all sorts of circumstances, but finally goes
to their doctor to get some help. The clues come from the history of heartburn
and indigestion, or maybe it was the extra aspirin or ibuprofen to help with
the stress headaches at work. There may be a little tenderness in the belly, and
after some coercion on the part of the doctor, the patient agrees to a rectal
exam. It shows that the stool has occult blood in it
(rectal bleeding); that is blood that cannot
be seen with the naked eye but shows up with a chemical test. A blood test (CBC) shows
that the patient is anemic, meaning there is a low
red blood cell count. Put the
clues together and the doctor tells the patient that the fatigue and tiredness
is due to bleeding.
Abdominal pain is pain in the belly and can be acute or chronic. Causes include inflammation, distention of an organ, and loss of the blood supply to an
Rectal bleeding (hematochezia) refers to the passage of bright red blood from the anus. Rectal bleeding may be moderate to severe and most bleeding comes
Anal itching is the irritation of the skin at the exit of the rectum, known as the anus, accompanied by the desire to scratch. Causes include everything
Inflammation of the inner lining of the colon is referred to as colitis. Symptoms of the inflammation of the colon lining include diarrhea, pain, and blood
Pancreatic cancer is a malignant tumor of the pancreas. Pancreatic cancer has been called a "silent" disease because early pancreatic cancer usually does
Gallstones are stones that form when substances in the bile harden. Gallstones (formed in the gallbladder) can be as small as a grain of sand or as large
Celiac disease is a result of an immune reaction to gluten, a protein found in wheat or related grains and present in many foods that we eat. Celiac disease
Gastritis is an inflammation of the stomach lining. Causes of gastritis include drinking too much alcohol, medications such as NSAIDs, ibuprofen, aspirin,
Cystic fibrosis is a disease of the mucus and sweat glands. Cystic fibrosis is an inherited disease. The outcome of the disease leaves the body malnourished,
Colon are common growths on the inner lining of the colon. Colon polyps may become cancerous. There are several different types of colon polyps, and the
Pancreatic cysts are collections of fluid within the pancreas. Some are benign, malignant, or pseudocysts. There are two major types of pancreatic cysts,
Intussusception is the telescoping (prolapse) of a portion of the intestine within another immediately adjacent portion of intestine. Intussusception affects
Hemophilia is one of a group of inherited bleeding disorders. Hemophilia A and B are inherited in an X-linked recessive genetic pattern and is more common
Hepatitis means inflammation of the liver. Hepatitis A (HAV, Hep A) is one type of liver disease caused by a virus. Since hepatitis A is a virus, it can
Idiopathic means that the cause of the condition isn't known. Thrombocytopenic means there's a lower than normal number of platelets in the blood. Purpura
Varices are dilated blood vessels usually in the esophagus or stomach. Symptoms of bleeding varices include vomiting blood, black stools, low blood pressure,
Nonsteroidal antiinflammatory drugs (NSAIDs) are prescribed medications for the treatment of inflammatory conditions. Examples of NSAIDs include aspirin,
Irritable bowel syndrome (IBS) in children is a functional gastrointestinal disorder with symptoms of abdominal pain, bloating, diarrhea or constipation.
Enterovirulent Escherichia coli (E. coli) are strains of related bacteria that have a strong propensity to cause gastrointestinal tract infections. Examples
