• A stool color other than brown, tan, yellow or green. Any shade of these is normal.

Causes

• Almost always due to food coloring or food additives. 
• Stool color relates more to what is eaten than to any disease.
• In children with diarrhea, the gastrointestinal (GI) passage time is very rapid. Stools often come out the same color as the Kool-Aid or Jell-O that went in. 
• The only colors we worry about are red, black (not dark green) and white.

Clues to Unusual Stool Colors

Red:

• "Bloody stools": 90% of red stools are NOT caused by blood
• Blood from lower GI tract bleeding
• Foods: red Jell-O, red or grape Kool-Aid, red cereals, red candy, red frosting, tomato juice or soup, tomato skin, cranberries, beets, red peppers, red licorice, Fire Cheetos
• Medicines: red medicines (e.g., Amoxicillin), occasionally other medicines that turn red in the GI tract (e.g., Omnicef)

Black:

• Blood from stomach bleeding (stomach acid turns blood to a dark, tar-like color)
• Foods: licorice, Oreo cookies, grape juice
• Medicines: iron, bismuth (e.g., Pepto-Bismol)
• Other: cigarette ashes, charcoal
• Bile: Dark green stools from bile may look black under poor lighting. Smearing a piece of stool on white paper and looking at it under a bright light often confirms that the color is actually dark green.

Green:

• Green stools are always normal, but they can be mistaken for black stools.
• Bile: Most dark green stools are caused by bile.
• Green stools are more common in formula fed than breast fed infants, but normal with both.
• Green stools are more common with diarrhea (rapid transit time), but also seen with formed stools.
• Foods: green Jell-O, grape-flavored Pedialyte (turns bright green), green fruit snacks, spinach or other leafy vegetables. Dark green stools (e.g., after eating spinach) may look black under poor lighting.
• Medicines: iron (e.g., in formula)

White Or Light Gray:

• Foods: milk-only diet
• Medicines: aluminum hydroxide (antacids), barium sulfate from barium enema
• Liver disease: Young infants with blocked bile ducts have stools that are light gray or pale yellow.