Short answer
Food dye, beets, leafy greens, carrots, blueberries, iron tablets and bismuth medicines such as Pepto-Bismol are among the most common reasons for a color change. These changes are usually harmless and usually clear within a day or two of stopping. Black tarry stool, blood, or pale and white stool are not explained by food and need checking.
Which foods, drinks and medicines change stool color?
Common food and medicine causes of stool color changes include leafy greens and green dye (green), beets and red dye (red), iron and bismuth (black), carrots and beta-carotene (orange), and barium (white).
| Color | Foods and drinks | Medicines and supplements |
|---|---|---|
| Green | Spinach, kale, broccoli, green smoothies, green or blue dye | Iron, some antibiotics (through loose stool) |
| Red | Beets, tomato products, red gelatin, fruit punch, red dye, cranberries | The antibiotic cefdinir, in babies on iron-fortified formula |
| Black | Black licorice, blueberries, black or dark blue dye | Iron, bismuth (Pepto-Bismol), activated charcoal |
| Orange | Carrots, sweet potato, squash, orange dye | Rifampin, aluminum-hydroxide antacids, beta-carotene supplements |
| Yellow | Turmeric, carrots, foods high in fat | Orlistat (oily stool) |
| Pale or white | None typical | Barium for X-rays, aluminum-hydroxide antacids |
| Blue or purple | Blue and purple dye, blueberries, grape drinks | None typical |
This table is not a complete list. Check the leaflet of any medicine or supplement, and ask your pharmacist whether it can change stool color.
Can food dye change stool color?
Blue, green, red and purple food coloring in drink mixes, frosting, candy and cereal can pass through the gut and color stool, sometimes blue or green. It usually clears within a day or two. Think back over what you ate in the last 48 hours. Read more about food coloring and poop color and blue or purple stool.
Can alcohol change stool color?
Alcohol can irritate the gut and cause loose stool. Heavy or regular drinking can also cause stomach and esophageal bleeding, which can make stool black and tarry or bloody, and liver disease, which can cause pale stool. Stool color changes with heavy drinking should be taken seriously.
Can antibiotics change stool color?
Antibiotics can change gut bacteria and cause loose stool that looks green or yellow. Severe, watery or bloody diarrhea during or after antibiotics can be C. difficile infection and needs medical advice. See can antibiotics change stool color.
How can you tell a food-related color change from a warning sign?
A color change is more likely harmless if you can link it to a food, dye or medicine and it clears within a day or two. Black tarry stool, blood, and pale or white stool are warning signs.
Usually harmless
- You can link the color to a food, dye or medicine
- It starts after and clears within a day or two of stopping
- You feel well
Call a doctor
- The color lasts more than a few days after you stop the suspected cause
- You cannot link it to anything you ate or took
Get care now
- Black, sticky, tar-like stool
- Red or maroon blood, especially with dizziness
- White or pale stool, particularly with yellow skin or in a baby
Warning signs to know
These are signs that published medical guidance says need prompt or urgent care. The list is not complete, and ticking boxes cannot tell you whether you are ill. If you are worried, contact a clinician whatever you tick.
Questions people ask
What foods turn poop black?
Black licorice, blueberries and foods with black or dark blue dye can. Iron supplements and bismuth medicines are more common causes.
What foods turn poop red?
Beets, tomato products, red gelatin, fruit punch and red food dye.
How long does food change stool color?
Usually one to three days. If it lasts longer with no cause you can point to, have it checked.
Can food dye turn poop blue or green?
Yes. Blue, purple and green dyes commonly do this, and it is usually harmless.
Sources
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