Gastroenterologist Brett Mendel, MD, knows poop, to say the least. But even he was perplexed when his wife called him concerned that their 11-month-old daughter’s diaper had black poop in it.
“Didn’t you say black poop is bad?” he recalls his wife asking. Indeed, black-colored poop in adults can be indicative of a serious health concern, says Dr. Mendel, of Atlanta Gastroenterology Associates. But the baby seemed fine, and the poop didn’t have a tar-like consistency, another sign in adults that something may be wrong.
Since he doesn’t specialize in pediatrics, Dr. Mendel did what most of us would do next: He consulted Dr. Google. There, he found a culprit he didn’t see while looking through his daughter’s diaper: blueberries.
“I was digging through poop,” he says. “But blueberries can turn baby poop black. I was unaware of this, so I was on a poop scavenger hunt.”
Luckily, his daughter’s black poop turned out to be nothing to worry about. But poop color and consistency can be a window into someone’s overall health and well-being, Dr. Mendel says. “It’s usually the first finding of changes in the body that could be much more meaningful.”
What color should your poop be?
“It is absolutely normal for stool to vary in color,” says Felice Schnoll-Sussman, MD, director of the Jay Monahan Center for Gastrointestinal Health at New York-Presbyterian and Weill Cornell Medicine.
Often, these color changes are due to foods in your diet, she says. But all shades of brown and most shades of green are considered normal.
“Brown is normally associated with the natural breakdown of bile in the GI tract,” says Dr. Mendel. Bile is secreted by the liver and helps to break down fat.
Poop that isn’t brown or green isn’t always cause for concern. But any time there’s a change of color or consistency in stool–or if you’re at all worried about your poop color and other symptoms–it doesn’t hurt to talk with a professional, Dr. Mendel says.
Often, poop that is green may be due to something in your diet, like green leafy vegetables or green food coloring. In some cases, you may even spot bits of vegetable roughage in your stool, like kale, says Dr. Mendel.
But green-colored poop may also be a sign that food is moving through the digestive tract too quickly without enough time for bile to turn stool brown. This can be due to diarrhea or something called “dumping syndrome,” Dr. Mendel says, which is most common after stomach or esophageal surgery.
Clay-colored stool or pale stool
Like black-colored poop, clay or pale stool sets off an alarm bell among GI specialists, Dr. Mendel says.
“It can indicate the absence of bile,” he says. “And a lot of times an obstruction of normal bile flow is one of the first indicators of pancreatic cancer.”
If there’s something serious going on like pancreatic cancer or liver disease, clay-colored or pale stool may also be accompanied by jaundice—a yellowing of the eyes and skin—which means bile is not being released into the GI tract.
People may notice yellow-colored poop in a few different situations. Often, it’s associated with fatty foods not breaking down all the way, which can be related to issues with the pancreas, Dr. Mendel says.
If the stool is yellow and also oily, greasy, and smells worse than usual, it might be a sign of celiac disease or an infection caused by the parasite giardia, he adds.
However, in babies, especially if they’re breast-fed, yellow-colored stool is considered normal.
While Dr. Mendel learned black-colored poop in babies may just be a sign of eating too many blueberries, in adults, it’s a sign that something serious could be going on.
Black poop is often an indicator of bleeding, typically in the upper GI tract—the stomach or the first part of the small intestine, called the duodenum. Blood in the upper GI tract can also give stool a tar-like consistency and could be due to ulcers, sores, or tumors. If you notice black, tar-like poop, seek medical attention immediately.
But black color alone isn’t always cause for concern. Pepto-Bismol, iron supplements, and even black licorice have been known to turn poop black. (The consistency in those cases is usually normal.)
While some foods, like beets and red gelatin, might cause reddish poop, a bright red color is often a sign of bleeding lower down in the intestinal tract.
If your poop is bright red, that’s something you should seek care for, says Dr. Mendel. Blood on toilet paper after straining to poop could be a sign of hemorrhoids, but blood coming into the toilet bowl could indicate diverticular bleeding or a malignancy in the colon.