Stool Color Changes
Benjamin Wedro, MD, FACEP, FAAEM
Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.
- Definition of stool color changes
- What is the color of normal stool?
- What are the symptoms of stool color changes?
- Green stools
- Yellow, greasy, and foul smelling stool
- Black tarry stools
- Bright red stools
- Light-colored white or clay-colored stools
- Maroon stools
- Mucous in the stool
- Stool that floats
- Changes in the size and shape of stool
- How is the cause of stool color changes diagnosed?
- When should I contact my doctor about stool color or texture changes?
- Stool color chart
- Patient Comments: Stool Color Changes - Color and Experience
- Patient Comments: Stool Color Changes - Symptoms
- Patient Comments: Stool Color Changes - Causes and Diagnosis
- Find a local Gastroenterologist in your town
Definition of stool color changes
It is reasonable to have an obsession with one's bowel movements. The quality, quantity and color of stool may be an indicator of gastrointestinal system's health and should the stool change color, it may provide a clue as to what might be wrong.
Stool, feces, or poop is the waste product of digestion. Food mixes with bile from the liver and digestive enzymes from the pancreas allowing protein, carbohydrates, and fats in the diet to be broken down to form a slurry. This liquid mixture passes through the small intestine where nutrients are absorbed into the blood stream and the liquid waste is delivered to the colon. In the colon, water is absorbed and stool is formed. Normal stool contains bacteria, digested food, cellulose from undigested plant material, and bile.
What is the color of normal stool?
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 are the symptoms of stool color changes?
Symptoms of stool color changes do not cause symptoms in most cases.
- Symptoms that may occur with changes of stool color are a result of the underlying cause of the change in stool color. For example:
- Diarrhea may produce green stools caused by a number of reasons.
- Abdominal pain may produce clay-colored stools.
- Back pain may signal a tumor blocking the bile ducts.
- Upper or lower abdominal pain (sometimes caused by bleeding in the GI tract.
- Nausea and vomiting associated with stool color changes may be from heavy associated bleeding.
If stool passes through the intestine too quickly, there might not be enough time for bile to be digested and broken down to provide the normal brownish stool color. Bile is a greenish brown fluid that is manufactured in the liver and stored in the gallbladder. Bile helps digest fats in food. It takes time for the bile to degrade and turn brown in the intestine and if the transit time is short, the stool remains green colored. This is why diarrhea is often greenish in color.
Green stools may be a normal variant. It can also be caused by a diet rich in green vegetables, especially spinach. Iron supplements also may be a cause, though it often turns stool black.
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