Stool Color Changes and Chart: What Does It Mean?

What Causes Changes in Stool Color, Form, or Texture?

If your stool is black, the cause might be an iron supplement or over-the-counter medicine you took because your stomach felt bad.

Stool color can change for a variety of reasons. The change may reflect substances that are added to stool or changes to substances normally present in the stool. Some stool color changes may suggest an underlying medical condition, and others may be due to the ingestion of certain foods or medications.

Black Stools (Not Sticky, No Odor)

Causes of black stool include iron pills or bismuth-containing medications (such as bismuth subsalicylate or Pepto-Bismol). If the stool color is dark because of any of these medications, it is typically not sticky in texture and is not foul-smelling.

Black Tarry, Sticky Stools

Bleeding in the stomach (from gastritis or an ulcer) or the intestines can change the color of the stool. If bleeding occurs in the stomach or the upper part of the small intestine, the stool may turn black and sticky, and be described medically as black, tarry stool (melena). Generally, the black, tarry stool also is foul-smelling. This change in color and consistency occurs because of chemical reactions to blood within the intestine that are caused by digestive enzymes within the intestines.

Maroon or Red Stools

If the bleeding originates from lower parts of the intestines or the colon, blood may not come into prolonged contact with digestive enzymes because of the short distance from the site of bleeding to the rectum. Moreover, large amounts of blood within the intestines speed up the transit of stool so that there is less time for the changes to take place. The stool in this type of bleeding may be dark red or maroon in color. Beets, other red vegetables, cranberries, and red food dyes also can turn the stool color red or maroon.

Gray or Clay-Colored Stool

The stool can be gray or clay-colored if it contains little or no bile. The pale color may signify a condition (biliary obstruction) where the flow of bile to the intestine is obstructed, such as obstruction of the bile duct from a tumor or gallstone in the duct or nearby pancreas. The change of stool color to gray or clay typically occurs gradually as these medical conditions progress relatively slowly and stool becomes pale over time.

Yellow Stool

Stool that is yellow may suggest the presence of undigested fat in the stool.

This can occur as a result of diseases of the pancreas that reduce delivery of digestive enzymes to the intestines (pancreatic insufficiency), such as:

• cystic fibrosis,
• chronic pancreatitis (long-standing inflammation and destruction of the pancreas usually due to alcohol abuse), or
• obstruction of the pancreatic duct that carries the enzymes to the intestines (most commonly due to pancreatic cancer).

Celiac disease: Another condition that possibly may cause yellow and greasy stool is celiac disease (a malabsorption syndrome).

The digestive enzymes released from the pancreas and into the intestines are necessary to help digest fat and other components of food (proteins, carbohydrates) in the intestines so that they can be absorbed into the body. If the pancreas is not delivering enzymes into the intestines, then components of food, especially the fat, can remain undigested and unabsorbed. The stool containing the undigested fat may appear yellowish in color, greasy, and also may smell foul.

Ingestion of very high-fat foods also can cause yellow, soft, and foul-smelling stools.

Weight loss medications such as orlistat (Xenical, Alli) work by limiting the amount of fat absorbed by the intestines. This can lead to bulky, yellow, and greasy stools.

Green Stool

When stool passes through the intestines rapidly (diarrhea), there may be little time for bilirubin to undergo its usual chemical changes, and stool can appear green in appearance due to rapid transit.

Eating excessive amounts of green foods, foods with green or purple dyes, and vegetables also can cause stool color to turn more green than normal.

What is the treatment for changes in the stool?

Treatment for changes in the stool depends on the symptoms and condition causing the changes.

Black stool

The treatment for black stool varies depending on the underlying condition or reason. If the dark-colored poop is caused by certain foods, stopping those foods will make the condition go away.

If the black stool is due to peptic ulcers, certain medications, such as proton pump inhibitors or PPI, may be prescribed by the doctor. You may also be advised to stop eating spicy foods. Your doctor may perform a procedure, such as an endoscopy (a procedure in which a flexible tube-like instrument with a camera and light source is used to view the inside of the gut), to treat a bleeding ulcer.

Depending on the extent of blood loss, you may need supplements or blood transfusion. If you are taking certain medications, such as aspirin or NSAIDs, your doctor may ask you to stop taking them.

You may need antibiotics or anti-protozoal medicines if the bleeding is due to certain infections.

Surgery and other appropriate therapy may be needed in case of variances and cancer.

Green stool

Green stools are generally harmless and will resolve on their own. If you want to treat green stools, there are several ways you can potentially return your stool to its standard shade.

If you've been eating large amounts of green vegetables, they are likely the cause. Reducing your spinach intake may return your stools to their normal color. Similarly, if you've started taking iron supplements, lowering your dose will likely help.

For short-term intestinal problems like gastroenteritis, your priority should be to keep yourself hydrated and comfortable. The illness should resolve by itself in a few days to a week and your stools will return to normal.

If your stomach problems continue for longer than a few days or you're having trouble staying hydrated, you should reach out to your physician for medical treatment.

Mucus in stool

Depending on the diagnosis, your doctor may advise medical treatment or simple home-based care. If it is an infection, your doctor will prescribe the necessary antibiotics and medicine to manage the symptoms.

Some conditions like mild food poisoning will only require you to drink more fluids and a diet change.

A clear diagnosis will help you and your doctor to find the best cure for your condition.

Oily stool (steatorrhea)

To treat steatorrhea, your underlying condition must be treated by a healthcare provider.

You may require pancreatic enzyme replacement therapy if you have exocrine pancreatic insufficiency.

• If your intestines are not getting enough bile, you might benefit from a bile acid replacement, such as Ursodiol (ursodeoxycholic acid).
• You may require additional treatment to avoid complications of fat malabsorption. Long-term fat malabsorption can result in severe fat-soluble vitamin deficiencies (A, D, E, and K).

Treatment for various levels of malnutrition and its complications could be required.