Stool Colors: What Changes May Mean and When to Get Help
Stool color can change from day to day. Food, supplements, medicines, bile and how quickly stool moves through the digestive tract can all affect its appearance. Many changes are harmless, but some colors—especially red, black and unusually pale stool—deserve closer attention.
Brown: the usual range
Most healthy stools are shades of brown. Bile changes as it travels through the intestine, contributing to stool color. A slightly different shade of brown from one day to the next is not usually a reason for alarm.
Green: often food or faster transit
Leafy vegetables, green food coloring and iron supplements can turn stool green. Green stool can also occur when food passes quickly through the intestine during diarrhea, leaving less time for bile pigments to change color. Seek medical advice if the change is persistent or accompanied by significant diarrhea, dehydration, fever or pain.
Yellow, greasy and difficult to flush
Yellow stool alone is not a diagnosis. But stool that is repeatedly oily or greasy, floats because of excess fat, smells unusually foul, or is hard to flush may suggest difficulty absorbing fat. Causes can include dietary factors and conditions affecting digestion or absorption. A clinician can evaluate persistent symptoms, particularly with weight loss or other concerns.
Pale, white or clay-colored
Very pale or clay-colored stool may mean that too little bile is reaching the intestine. This can occur with conditions involving the liver, gallbladder or bile ducts and some medicines or imaging substances. Seek prompt medical evaluation if the change persists; do not ignore pale stool accompanied by yellow skin or eyes (jaundice), dark urine, fever or abdominal pain.
Black or tarry: do not dismiss possible bleeding
Iron tablets, bismuth-containing medicines and some dark foods can make stool appear black. However, black, sticky, tar-like stool may indicate bleeding in the upper gastrointestinal tract. Seek urgent medical assessment, especially if you also feel dizzy, weak, short of breath or have abdominal pain. Do not assume black stool is caused by a food or supplement without considering possible bleeding.
Bright red or maroon: blood needs evaluation
Beets, red food coloring and some foods can change stool color. Bright red blood on stool or toilet paper may occur with hemorrhoids or a small anal tear, but bleeding can have other causes. Red or maroon blood mixed with stool can signal intestinal bleeding. Seek medical advice promptly; seek emergency help for heavy bleeding, fainting or signs of shock.
When to contact a healthcare professional
Tell a healthcare professional about unexplained, persistent color changes, blood, very pale stool, persistent greasy stool, ongoing diarrhea, or new symptoms including fever, pain and unexplained weight loss. An occasional color change after a recognizable food may resolve on its own, but stool color alone cannot confirm the cause.
This article is for general information and does not replace individual medical assessment.
Sources
- Mayo Clinic — Stool Color: When to Worry
- NIDDK — Symptoms and Causes of GI Bleeding
- MedlinePlus — Pale or Clay-Colored Stools
