Why Is My Poop Green? Here Are 5 Possible Causes

While poop is typically brown, it can come in a range of colors, including tan, red, yellow, black, and green.

The color of your poop offers a glimpse into your gut and digestive health, giving you information on fiber and water intake, potential infections or health conditions, and stress levels, says Kumar Desai, MD , a gastroenterologist in Thousand Oaks, California.

So, what does it mean if your poop is green? And when should you see a doctor?

5 Potential Reasons Your Poop Is Green

Green poop isn't necessarily cause for alarm. Still, it can tell you about your diet and potential health conditions. Here are a few potential explanations for green poop.

1. You Eat a Lot of Green Foods

Natural and artificial pigments in foods tend to be the most common culprit for green poop, says Adrienna Jirik, MD , a gastroenterologist at the Cleveland Clinic in Ohio. "Stool color can change throughout the day and week depending on what you're eating."

Green leafy vegetables, for example, contain chlorophyll, a natural compound that gives them their color.

If you ingest enough, your stool will have a green hue, and you may have more bowel movements, Dr. Jirik says. Other foods that may make your stool green include avocado, matcha (powdered green tea), blueberries, pistachio, basil, cilantro, parsley, and foods with green dye or food coloring, says Supriya Rao, MD , a board-certified gastroenterology, internal medicine, obesity medicine, and lifestyle medicine physician in Boston.

2. You're Sick

Whether it's a virus or a bacterial infection, falling ill can cause your gastrointestinal (GI) system to speed up, leading to stools colored green by bile, Dr. Rao says.

Bile is a greenish-yellow fluid produced by the liver and stored in the gallbladder. It helps break down food, especially fats, during the digestive process.

Bacteria and viruses damage the digestive tissues, causing transit time to speed up. As a result, bile doesn't have enough time to break down your food and whatever you eat will come out greenish-yellow from the bile pigment, Rao says.

You'll know illness is to blame if you experience bloating, diarrhea, and nausea before green poop appears. "A lot of people experience these symptoms first," Rao notes.

3. You're Taking Antibiotics

If you have a bacterial infection, your doctor may prescribe antibiotics to kill the bacteria and prevent regrowth. But the medication tampers with your gut microbiome (the microbes that live in your intestines), killing bacteria responsible for the brown color of your poop, Rao says.

The result? Your poop may be green or yellowish in color.

4. You're Taking a Supplement

Iron supplements can also stool discoloration (though it more commonly causes stool to turn black). This is a known side effect of iron supplements, so don't be concerned, Dr. Desai says.

Supplements that contain chlorophyll - such as wheatgrass, spirulina, barley grass, and blue-green algae - may also cause greenish-colored poop, Rao says.

5. You've Just Had Gallbladder or Bariatric Surgery

If you recently had surgery to remove the gallbladder (cholecystectomy), you may see green or yellow stools for weeks or even months post-op as your body adjusts to the loss of its bile storage organ.

"The body needs time to acclimate to excess bile in the GI tract," Desai explains.

Similarly, people who undergo bariatric surgery (a weight loss procedure in which surgeons shrink the stomach) may have green stools for weeks or months afterward, Rao says. Because your stomach has shrunk and your small intestine is shorter post-op, you eat less and your body has less time to absorb calories. This speeds up transit time, causing your body to push out green stools until it readjusts, Rao says.

When to See a Doctor About Green Poop

Rao suggests visiting your primary care physician (PCP) doctor if you encounter green poop alongside symptoms, such as:

• Stomach pain or cramping
• Constipation or diarrhea
• Fever and flu-like symptoms
• Nausea
• Signs of dehydration, such as dark urine, dizziness, dry mouth, and fatigue

Your doctor may check for GI conditions, food intolerances, viral or bacterial infections, and other underlying causes that might explain your green stool.

The Takeaway

Green poop is common and often harmless, especially when caused by green foods and supplements or antibiotics. But it may also be the result of a health condition or illness. See your healthcare provider if you also have other persistent GI symptoms such as stomach pain, weight loss, constipation or diarrhea, flu-like symptoms, nausea, or signs of dehydration.

Editorial Sources and Fact-Checking

Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy . We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.

Sources

1. Liquid Chlorophyll: The Miracle Green? OSF HealthCare . March 7, 2023.
2. 3 Reasons Why Your Poop Is Green. Cleveland Clinic . August 27, 2021.
3. Bile. Cleveland Clinic . May 13, 2024.

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Yuying Luo, MD

Medical Reviewer

Yuying Luo, MD, is an assistant professor of medicine at Mount Sinai West and Morningside in New York City. She aims to deliver evidence-based, patient-centered, and holistic care for her patients.

Her clinical and research focus includes patients with disorders of gut-brain interaction such as irritable bowel syndrome and functional dyspepsia; patients with lower gastrointestinal motility (constipation) disorders and defecatory and anorectal disorders (such as dyssynergic defecation); and women's gastrointestinal health.

She graduated from Harvard with a bachelor's degree in molecular and cellular biology and received her MD from the NYU Grossman School of Medicine. She completed her residency in internal medicine at the Icahn School of Medicine at Mount Sinai, where she was also chief resident. She completed her gastroenterology fellowship at Mount Sinai Hospital and was also chief fellow.

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Carmen Chai

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Carmen Chai is a Canadian journalist and award-winning health reporter. Her interests include emerging medical research, exercise, nutrition, mental health, and maternal and pediatric health. She has covered global healthcare issues, including outbreaks of the Ebola and Zika viruses, anti-vaccination movements, and chronic diseases like obesity and Alzheimer's.

Chai was a national health reporter at Global News in Toronto for 5 years, where she won multiple awards, including the Canadian Medical Association award for health reporting. Her work has also appeared in the Toronto Star , Vancouver Province, and the National Post . She received a bachelor's degree in journalism from Ryerson University in Toronto.

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