Why Is My Poop Green? 5 Causes According to Gut Doctors

Discover why your No. 2 changes color and what it means for your health.

Adam Meyer is a health writer, certified holistic nutritionist and 100% plant-based athlete. In addition to EatingWell, his work has been featured on The Beet, Verywell Fit, The Healthy, Livestrong, Alive, Best Life and others. He graduated from the NutraPhoria School of Holistic Nutrition in 2019 and has since founded Pillars Nutrition.

Maria Laura is EatingWell's senior nutrition & news editor. As part of the nutrition team, she edits and assigns nutrition-related content and provides nutrition reviews for articles. Maria Laura is a trained dietitian, almond butter lover and food enthusiast with over seven years of experience in nutrition counseling.

If you've ever answered nature's call and encountered a mysterious, unexpected shade of green, you're not alone. While green poop is often due to dietary factors like eating leafy greens or green-colored foods, sometimes rapid transit through your digestive system doesn't allow enough time for the bile pigment to be fully broken down and absorbed, resulting in a distinctly green hue.

Here, we explore why your poop is green and answer frequently asked questions, like should you be concerned when you pass green stool? Why is brown the usual color? And when should you see your doctor? Keep reading to learn more.

Eating too many green foods, whether with food dyes or naturally colored, can turn your poop green. More specifically, leafy greens like spinach, kale and Swiss chard are rich in chlorophyll, the green pigment that can temporarily tint your stool, per MedlinePlus, a resource of the National Library of Medicine. While it might be surprising, it's usually harmless and a sign that your body is making the most of those nutritious greens.

Sarah Robbins, M.D., MSC, FRCPC, a gastroenterologist and the founder of Well Sunday, tells EatingWell, "Consuming large amounts of green, leafy vegetables, such as spinach or kale, can result in green stools. Food coloring and certain dyes in processed foods or drinks can also change stool color."

"If food moves too quickly through the intestines, bile doesn't have time to break down completely," says Robbins. "Bile is a greenish-yellow fluid produced by the liver, stored in the gallbladder, and released into the intestines to help digest fats. When stool passes through the intestines rapidly, bile can still be green, leading to green stools."

A rapid transit time could happen due to different causes, such as food poisoning, gastrointestinal conditions and the use of laxatives. It's important to discuss this with your health care provider to identify the root cause and determine whether it's a concern or not.

Certain medications or supplements can play a role in changing the color of your stool. "Iron supplements can result in green or black stools. Also, certain antibiotics can lead to green stools by altering the gut's microbial balance," says Robbins.

Harmful bacteria can interfere with digestion, affecting how your body breaks down and absorbs nutrients. If your green poop is accompanied by other symptoms like diarrhea, fever or abdominal pain, seek medical attention to rule out potential infections.

"Certain bacterial infections, such as those caused by Salmonella or Giardia, can lead to green diarrhea," says Robbins. "The green color can result from the rapid transit time associated with diarrheal illness or the microbial activity in the gut."

Digestive conditions, like irritable bowel syndrome (IBS) or other functional gut disorders, can influence the color and consistency of your stool. These disorders can impact how your intestines move and process food, leading to changes in poop color.

"Functional disorders like IBS might occasionally result in green stools, especially during episodes of diarrhea or rapid transit," states Robbins.

Poop's brown color traces back to a substance called bilirubin, a component of your bile. This yellow compound is formed when your body breaks down old red blood cells, per StatPearls. As bilirubin travels through your liver and gallbladder, it transforms into a stercobilin—a compound responsible for giving stool its brown shade.

"Stool is typically different shades of brown from bile mixing with stool as it travels through the healthy gastrointestinal tract," explains Supriya Rao, M.D., a board-certified physician in gastroenterology and lifestyle medicine physician.

If your stool appears pale or clay-colored, it could indicate a problem with your liver, gallbladder or bile ducts, notes MedlinePlus. Bile gives your poop that brown hue, so disrupting its flow might lead to the absence of color.

"Light-colored or clay-colored stool can indicate a lack of bile. This may be due to a blockage of bile ducts, liver diseases or issues with the gallbladder, like gallstones," says Robbins.

If you find a surprising red or black shade in the toilet, it could signify bleeding in your gastrointestinal tract. According to the National Institute of Diabetes and Digestive and Kidney Diseases, red poop might suggest bleeding lower in your digestive system, possibly from hemorrhoids or anal fissures. Conversely, black stool could indicate higher bleeding from ulcers, polyps or gastritis.

"If you have red or black stools, see a physician to evaluate for potential intestinal bleeding from hemorrhoids, ulcers, inflammatory conditions like Crohn's disease or ulcerative colitis, and even colon cancer," advises Rao.

Robbins says, "Certain signs and symptoms related to stool may indicate underlying gastrointestinal conditions that necessitate a visit to a primary care physician or a specialist."

Robbin notes that the following signs and symptoms may indicate an underlying condition:

Green poop on its own is typically not a sign of cancer. However, if you're consistently experiencing unusual color changes accompanied by other concerning symptoms like blood in stool, extreme weight loss or persistent pain, consult a health care professional for proper evaluation.

In most cases, green poop isn't a cause for alarm. It can often be attributed to dietary choices, such as consuming leafy greens or foods with green food coloring. However, talk to your doctor if the green color and other symptoms persist.

If your green poop is due to dietary factors, there's usually no need to try to change it actively. However, if you're experiencing discomfort, such as diarrhea or cramping, consider adjusting your diet and seek medical guidance.

Green poop is not uncommon and is often due to dietary choices, like consuming leafy greens or foods with green coloring. Rapid digestion can also prevent bile pigment from breaking down completely, leading to a green tint.

Other causes include certain medications, bacterial infections, gut disorders and green food dye. If you experience other symptoms of gastrointestinal discomfort along with your green poop, or it lasts longer than a few days, visit your health care provider for proper assessment.