Unusual Stool Colors: Red, Black, Green, Orange, or Pale

When should you worry about the color of your stool?

Having black, red, green, orange, or clay-colored stools can be a frightening experience. Changes in the color, consistency, and frequency of bowel movements is known as a "change in bowel habits." Most people have experienced infrequent bouts of diarrhea, constipation, or a strange discoloration of their stool at one time or another.

In some cases, an unusual stool color is harmless and can be attributed to a particular food or medication -- but not always. Changes in bowel habits that persist can be a serious matter and should always be investigated by a physician.

Black or red stools can indicate internal bleeding somewhere in the gastrointestinal tract. Black, tarry stool that has a distinctive odor is called melena, and is caused by bleeding in the upper digestive tract. Stool that is red in color because it contains blood is called hematochezia. In the case of hematochezia, blood may coat the stool, be mixed in with the stool, or even be passed without any stool at all.

• acidified blood (blood from higher in the digestive tract)
• iron supplements or foods high in iron
• Pepto-Bismol or other medicines containing bismuth
• black licorice
• large amounts of spinach or other greens
• blueberries
• other foods dark in color

• blood (such as from hemorrhoids, anal fissures, or diverticualr disease)
• red gelatin, popsicles, or food containing artificial red coloring
• tomato juice or soup
• large amounts beets

• liver disease (such as hepatitis or obstruction of bile ducts)
• antacids containing aluminum hydroxide
• barium from a recent barium enema test

• large amounts of green, leafy vegetables
• green or purple artificial coloring (popsicles, Kool-Aid, gelatin)
• iron supplements
• infectious gastroenteritis
• rapid bowel transit or decreased colonic transit time

• some medications (such as beta-carotene and Rifampen)
• foods high in beta-carotene: carrots, sweet potatoes, apricots, winter squash, pumpkin, cantaloupe, and mangoes

If a change in stool color cannot be attributed to a dietary reason, or is accompanied by any other symptoms (such as diarrhea, constipation, weakness, or dizziness), a doctor should be consulted.

_Sources:

_{National Institute of Diabetes and Digestive and Kidney Diseases. "Bleeding in the Digestive Tract." National Digestive Diseases Information Clearinghouse. November 2004. 22 Apr 2009.}

_{A.D.A.M. Health Illustrated Encyclopedia. "Bloody or tarry stools." A.D.A.M. 25 July 2007. 22 Apr 2009.}

_{A.D.A.M. Health Illustrated Encyclopedia. "Stools - pale or clay-colored." A.D.A.M. 8 Aug 2008. 23 Apr 2009.}