Stool Color Changes (cont.)

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How is the cause of stool color changes diagnosed?

In most cases, a diagnosis, if any, cannot be made by stool color alone.

The patient and the doctor need to consider other symptoms, past medical history, dietary changes, and medications to help decide what has caused the stool to change color. Physical examination will be important to help decide the significance of the stool color.

Stool may be tested to look for blood, fat, or infection. Blood tests may be necessary depending upon the clinical situation. Depending on the change in color, it may be necessary to evaluate the pancreas, liver or GI tract.

When should I contact my doctor about stool color or texture changes?

Aside from black, red, or maroon stools that may signify bleeding and require urgent assessment and treatment, most color changes are not an emergency. The significance is determined based on other symptoms that might be present.

Women who are pregnant often note changes in their bowel pattern. Stool can turn black because of iron and vitamin supplements. Iron can also turn stool greenish. As the uterus enlarges and increases pressure within the pelvis, constipation may occur and hemorrhoids can develop and cause blood in the stool.

If there is no underlying problem, stool color changes are often due to changes in the diet and will resolve in a couple of days. If this is not the case and changes persist, it is appropriate to contact your doctor and seek medical attention.

Contact your doctor if you have stool color changes and have associated symptoms such as vomiting, diarrhea, fever or abdominal pain.

It is important to remember that every person is different and changes in bowel habit be it color, size, frequency, or consistency (hard or soft) may be normal for one person or a sign of a potential problem for another.

Stool color chart

Stool Color Changes
Potential CauseCommentSub-Header
BlackGI bleedingThis is an emergency
BlackIron, bismuthCannot presume this to be the reason for the stool color
MaroonGI bleedingThis is an emergency
RedHemorrhoidsOnly one of the potential causes. Do not ignore
RedInflammatory bowel diseaseConsult doctor
RedInfection, diverticular bleedConsult doctor
RedTumor, rapid upper GI bleedConsult doctor
GreenMay be normalConsult doctor
GreenDiet high in green vegetablesConsult doctor
GreenAssociated with diarrheaConsult doctor
BrownNormal colorConsult doctor
YellowDiseases of the pancreasMalabsorption
YellowCeliac disease, cystic fibrosisConsult doctor
Yellow Giardia infectionConsult doctor
Clay, pale yellow or whiteLiver or biliary diseaseLack of bile in the stool


Longo DL. et al. Harrison's Principles of Internal Medicine. McGraw-Hill Professional. 18th edition. 2011.

Medically Reviewed by a Doctor on 9/16/2015

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Stool Color Changes - Color and Experience Question: What color, texture, or smell; is or was your stool when it changed? Please share your experience.
Stool Color Changes - Symptoms Question: What symptoms did you experience with changes in stool color, texture, or form?
Stool Color Changes - Contacting a Doctor Question: What prompted you to contact a doctor about changes in stool changes?
Stool Color Changes - Causes and Diagnosis Question: What was the cause of your stool to change (in color, texture, odor, etc.); and how was the diagnosis of the cause made?
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Stool Color Changes - Size and Shape Symptoms Question: What symptoms did you have with changes in the size and shape of your stool, and if known, what was the cause?