While the exact subject of this article may not make for polite conversation, it is still imperative that you know some basic facts about stool color. Being aware of your stools’ hue can help decode possible health or dietary concerns. That being said, the color of expelled wastes reveals more than what you ate last night. What, then, could it mean? Well, these next 10 facts explain.
1. Bacteria + Bile + Fat + Iron = Brown
As you might expect, a brown hue means the gastrointestinal tract is healthy, the liver is working right, and you’ve got a good balance of those helpful, friendly bacteria in your system. Bile, iron, fat, and bacteria combine to create the brown color we’ve all come to expect.
2. Pale or Gray: Don’t Panic
A pale-colored stool does mean you should pay attention, but it doesn’t necessarily mean there is a serious medical issue. Pale stools occur for two reasons. The first reason may simply be warning you of a possible iron deficiency. In this case, increase consumption of iron-rich foods such as spinach, turkey, beans, broccoli, salmon, red meat, or liver. If the color returns to normal, no problem. If it remains pale, then it may reflect a liver problem or blocked bile ducts. In this case, see a doctor.
3. Green: The Color of Bile
If bowel movements come out green, then the wastes have passed too quickly. Bile combines in the small intestine with chyme, the partially-digested food which passes from the stomach to small intestine. When poop comes out green, it means the food passed very quickly through the gastrointestinal tract and the bile did not have the opportunity to process the food. Reasons for this could be food poisoning, a stomach bug, celiac disease, IBS, laxative use, GI diseases (ulcerative colitis or Crohn’s disease, for example), alcohol consumption, or cancer. Perhaps you consumed a large amount of food containing green food dye, or maybe you ate too many blueberries or juiced with super green vegetables.
4. Yellow Stool: Warning
During digestion, food transitions from green to yellow, then ideally to brown. The yellow hue indicates that bile did not have time to break down fats present in the food. GERD (reflux disease), celiac disease, and parasites such as giardia can lead to a faster bowel transit time, reflected in yellow stool. Other possible causes of yellow stool include liver, gallbladder, and pancreatic diseases, all of which may reduce available bile and the ability to breakdown fats. This can lead to steatorrhea, or stool with unusually high levels of fats.
5. Bright Blue? No Worries
That’s right, if you see a decidedly blue color, think back to what had food dye. Vibrant colors such as blue or green in normal (not loose) looking stool generally reflects the consumption of a non-digestible food dye. This discoloration should pass after a few bowel movements. A dark, deep blue may also indicate a diet high in protein. This happens when the protein does not move through the bowel quickly enough, often resulting in putrefaction of the fecal matter in the bowels.
6. Red May Not be Blood
But more likely than not, it probably is.  You ought to see a doctor right away as red stools often mean bleeding in the colon, rectum, or anus. Of course, red food coloring or consuming beets, beet juice, or tomato juice could give stool a red-ish color. If you didn’t eat any of these foods or consume any red food dye, see a doctor.
7. If It’s Black, Get Medical Attention
Iron supplements, anti-diarrheal medicines like Pepto-Bismol, or black licorice can lend a dark or blackish hue to stool. If it’s hard and black and passed after a bout of constipation, the color may be a result of the constipation. Absent these, black stool means blood has entered the digestive tract somewhere in the stomach or small intestine. Red may also be present if it is in fact a result from bleeding.
8. Parasites Create Various, Unusual Colors
Parasitic infection of the digestive tract can lead to a wide range of colors. Hues may be red-orange, red-black, green, grey, or even red-brown. Parasites like giardia can cause symptoms like food poisoning; others can cause bleeding. In this case, stick to the general rule: if red or black presents in the stool, seek medical help.
9. Stress Causes Discoloration
Anxiety and stress can disrupt digestion and cause food to move through the digestive tract too fast. Yellow-colored stools are the most common result. Persistent high levels of stress with regular yellow-colored poop will result in inadequate nutrition and reduce the body’s ability to naturally combat stress. Seek help when stress and anxiety become a constant feeling.
10. Don’t Let Poop Color Cause Panic
Some colors can be shocking, especially those from indigestible food dyes. Others may just seem odd. Stool color doesn’t just happen, though. If there’s a problem, additional symptoms like bloating or gas may exist. Frequent trips to the washroom may be occurring, and the consistency may be loose, hard, or slimy. And then, of course, a foul smell will accompany inadequate digestion and gastrointestinal disorders.
My advice to you is this: if the color of your poop looks off and you’re not sure if you should see a doctor, trust your gut.
-Dr. Edward F. Group III, DC, ND, DACBN, DCBCN, DABFM
- PubMed Health. Blood or tarry stools. A.D.A.M. Medical Encyclopedia.