Healthy poop is typically some shade of brown, ranging from light tan to dark brown. That color comes from a pigment called stercobilin, which forms when bacteria in your colon break down bile (a digestive fluid your liver produces). When something disrupts that process, or when certain foods and medications pass through your system, stool can turn green, yellow, red, black, pale, or orange. Most color changes are harmless and temporary, but a few signal something that needs medical attention.
Why Normal Poop Is Brown
Your liver constantly produces bile to help digest fats. Bile contains a yellow-green pigment called bilirubin, which is a byproduct of old red blood cells being recycled. As bile travels through your intestines, gut bacteria convert about 80% of that bilirubin into stercobilin, the pigment responsible for brown stool. Anything that changes how much bile reaches your intestines, how fast food moves through, or what you’ve eaten can shift the color.
Green Stool
Green poop is one of the most common color variations, and it’s almost always harmless. The two main causes are diet and speed of digestion.
Leafy greens like spinach, kale, and broccoli contain chlorophyll, which can tint stool green if you eat enough of them. Green food coloring in drink mixes, ice pops, and candies does the same thing. Iron supplements are another frequent culprit.
The other explanation is rapid transit time. When food moves through your colon faster than usual, such as during a bout of diarrhea, bile doesn’t have enough time to be fully broken down by bacteria. Since bile starts out yellow-green, stool that passes quickly retains that greenish color instead of turning brown. If green stool shows up alongside diarrhea and resolves within a day or two, it’s nothing to worry about.
Yellow or Greasy Stool
Occasionally yellow stool is just the result of eating a lot of yellow-colored foods like sweet potatoes or turmeric-heavy meals. But consistently yellow, greasy, foul-smelling stool points to a condition called steatorrhea, which means your body isn’t absorbing fat properly. These stools tend to be looser than normal, paler (sometimes clay-like), and noticeably smellier.
Fat malabsorption happens for two main reasons. The first is that your pancreas isn’t producing enough digestive enzymes, a condition called exocrine pancreatic insufficiency. Chronic pancreatitis is one of the most common causes. The second is damage to the lining of your small intestine, which prevents it from absorbing fats even after they’ve been broken down. Celiac disease is a well-known example. If your stool is persistently yellow, oily, or floats and is difficult to flush, that pattern is worth bringing up with a doctor.
Red or Bloody Stool
Red stool gets people’s attention, and rightfully so, but food is actually the most common explanation. Beets, tomato soup, red gelatin, cranberries, and red food dyes can all turn stool reddish without any bleeding involved. If you ate something red in the last day or two, that’s likely the cause.
Bright red blood in or on your stool, on the other hand, typically means bleeding somewhere in the lower digestive tract: the colon, rectum, or anus. Hemorrhoids are the single most common cause. They’re swollen veins in the rectum or anus, and they often produce small amounts of bright red blood on toilet paper or on the surface of the stool. Anal fissures, which are small tears in the lining of the anal canal, cause similar symptoms.
More serious causes include inflammatory bowel disease (Crohn’s disease and ulcerative colitis), diverticulitis (infected pouches in the colon wall), colon polyps, and colorectal cancer. Bacterial infections like E. coli and C. diff can also cause bloody diarrhea. Blood-thinning medications sometimes contribute to rectal bleeding as well. Any rectal bleeding that is heavy, recurrent, or accompanied by pain, fever, or unexplained weight loss warrants prompt evaluation.
Black or Tarry Stool
Black stool has a short list of harmless causes: iron supplements, bismuth subsalicylate (the active ingredient in Pepto-Bismol), and foods like black licorice or blueberries in large quantities. These produce a dark color without any dangerous implications.
The concerning version is stool that’s not just dark but tarry, sticky, and unusually foul-smelling. That appearance suggests digested blood from the upper digestive tract, such as the stomach or upper small intestine. Blood that travels the full length of the digestive system gets broken down along the way, turning black rather than red. Peptic ulcers are a common source. If you haven’t taken iron or bismuth and your stool is black and tar-like, that needs medical attention quickly.
Pale, White, or Clay-Colored Stool
Pale or clay-colored stool is one of the more medically significant color changes because it signals a problem with bile flow. Since bile is what gives stool its brown color, a lack of bile reaching the intestines leaves stool looking grayish-white or like light clay.
The most common cause is an issue somewhere in the biliary system, which includes your liver, gallbladder, and bile ducts. Gallstones can physically block the bile duct. Hepatitis (whether viral, alcohol-related, or toxic) inflames the liver and disrupts bile production. Cirrhosis, fatty liver disease, and narrowing of the bile ducts (biliary strictures) can all have the same effect. Tumors or cysts on the liver, bile ducts, gallbladder, or pancreas may also obstruct bile flow. Pancreatitis is another possible cause. Persistently pale stool is not something to wait on, because most of its causes involve the liver, gallbladder, or pancreas and benefit from early diagnosis.
One exception: certain antacids containing aluminum hydroxide can temporarily lighten stool color. If you’ve recently started an antacid and notice pale stools, that’s a likely explanation, but mention it to your doctor if it continues.
Orange Stool
Orange poop is almost always a food thing. Beta carotene, the pigment that makes carrots, sweet potatoes, and winter squash orange, passes through your digestive system and can tint your stool the same color. Eating large amounts of these foods, or taking beta carotene supplements, is the most common cause.
Certain medications can also produce orange stool. The antibiotic rifampin is well known for turning body fluids (including stool and urine) an orange-red color. Some antacids containing aluminum hydroxide may produce orange or gray stool. These effects are harmless and stop once you discontinue the medication or supplement.
Stool Color in Babies
Infant stool follows its own color timeline and can alarm new parents who aren’t expecting it. A newborn’s first bowel movements are meconium: thick, sticky, and black-green. This is completely normal and typically clears within the first few days of life.
After meconium passes, stool transitions through a range of colors. Breastfed babies commonly produce mustardy yellow stool, which is the expected baseline. Formula-fed babies tend toward yellow-tan with hints of green. Varying shades of yellow, brown, and green are all considered normal in infants. The colors to watch for in babies are the same as in adults: white or clay-colored stool (which can indicate biliary atresia, a serious condition where bile ducts don’t develop properly), red stool not explained by food, and black stool after the meconium stage has passed.
Foods vs. Medical Causes: How to Tell
The simplest test is time. Food-related color changes are temporary, usually resolving within one to three days once you stop eating the trigger food. If you ate a large beet salad yesterday and your stool looks reddish today, give it a day or two. The same applies to green vegetables, orange carrots, and foods with artificial coloring.
Color changes that persist beyond a few days without an obvious dietary explanation deserve more attention. The same is true for any stool color change accompanied by other symptoms: abdominal pain, fever, unintended weight loss, persistent diarrhea, or visible blood. Pale or clay-colored stool and black tarry stool are the two colors that most consistently point to conditions requiring medical evaluation, regardless of whether other symptoms are present.